FUNGI  PARASITIC  UPON  ALEYRODES  GITRI 


By 
HOWARD  S.  FAWCETT 


A    THESIS    FOR    THE    DEGREE    OF    MA.-1  -CIENCK 

SUBMITTED    TO   THE     FArUKT 

THE  UNIVERSITY  OF  THE  STATE  OF  FLORIDA 

JUNK,  1908. 


FUNGI  PARASITIC  UPON  ALEYRODES  CITRI 

TTt-\~' 

U'NrvEK 

-or 

' 


By 

HOWARD  S.   FAWCETT 


A    THESIS    FOR  THE    DEGREE    OF    MASTER   OF    SCIENCE 
SUBMITTED    TO    THE    FACULTY    OF 

THE  UNIVERSITY  OF  THE  STATE  OF  FLORIDA 

JUNE,   1908. 


UNIVERSITY  OF  THE  STATE  OF  FLORIDA 
SPECIAL  STUDIES  No.  i 


CONTENTS. 


ENTOMOLOGY 
UBfiABY 


PAGE. 

I.  INTRODUCTION    5 

Statement  of  Work  on  Which  the  Thesis  is  Based 777 . . .  ,-rv . . , 5 

Historical   Review   of  Entomogenous   Fungi 5 

Historical  Review  and  Economic  Status  of  Aleyrodes  citri   R.   &   H 8 

II.  ASCHERSONIA     ALEYRODIS     WEBBER 10 

Discovery  and  Description    10 

History     10 

Methods  of  Introduction 11 

Germination   of    Conidia 12 

Cultures    13 

Infection  of  Aleyrodes  citri  from  Cultures 16 

Distribution     17 

III.  ASCHERSONIA  FLAVO-CITRINA  P.  HENN 11 

Discovery  and  Description • 11 

Comparison  with  A.  aleyrodis 18 

Cultures    18 

Germination  of  Conidia   39 

Super-parasite    21 

List  of  Localities  in  Florida 21 

IV.  VERTICILLIUM  HETEROCLADUM  PENZ 21 

Discovery  and  History  21 

Description    22 

Cultures    23 

Germination  of  Conidia   24 

Infection  of  Aleyrodes  citri  from  Cultures 24 

List  of  Insects  Parasitized,  with  Localities 25 

V.  Sl'H  AEROSTILBE    COCCOPHILA     Tui 25 

Description    25 

History     26 

Relation  to  San  Jose  and  Other  Scale  Insects 27 

Parasitism  on  Aleyrodes  citri 28 

List  of  Insects  Parasitized,  with  Localities 29 

VI.  M  ICROCERA    SP 29 

Technical  Description   ' 29 

Discovery     30 

Cultures    30 

Infection  of  Aleyrodes  citri   from  Cultures 32 

Germination  of  Conidia   33 

Variation  in  size  of  Conidia  33 

Distribution  in  Florida  34 

VII.  THE  "BROWN  FUNGUS"  34 

Discovery     34 

Description  by  Webber 34 

Brown  fungus  of  Parkin 35 

Methods  of  Introduction  35 

Distribution     36 

SUPPLEMENTARY   NOTES    36 

SUMMARY    ?>1 

BIBLIOGRAPHY    :58 

EXPLANATION  OF  PLATES.. 41 


272696 


LIST  OF  ILLUSTRATIONS. 

PACK. 

Fig.     1. — Adult  and  egg  of  .llcyrodcs   citri facing      8 

Fig.     2. — Larvae  and  pupae  of  Alcyrodcs  citri : facing      9 

Fig.     3. — Conidia  of  Aschcrsonia  alcyrodis 12 

Fig.     4. — Conidium  of  Aschcrsonia  alcyrodis  germinating 13 

Fig.     5. — Hyphae  of  Aschcrsonia  flaro-citrina H» 

Fig.     6. — Conidia  of  Aschcrsonia  flaro-citrina 1 (.) 

Figs.  7,  8  and  9. — Sporids  of  Aschcrsonia  flavo-citrina 20 

Fig.  10. — Conidiophores  and  conidia  of  /  'crticilliitm  hctcrocladnin 23 

Fig.  11. — Spore-like  bodies  of  I 'crticillinin  hctcrocladnin 23 

Fig.  12. — Perithecium  of  Spkaerostilbe   coccophila 2,~> 

Fig.  13. — ASCIIS  of  Sphacrostilbc  coccophila 2."> 

Fig.  14. — Sporodochium   of  $j  hacrostilbc   coccophila 2(5 

Fig.  15. — Conidia  of  Sphacrostilbc  coccophila 26 

Fig.  16. — Hypha  and  conidia  of  Microccra  sp 30 

Fig.  17. — Conidia  of  Microccra  sp 30 

Fie.  18. — Conidia  of  Microccra  sp 30 

Fig.  19. — Sporids  of  Microccra  sp 33 

Figs.  20.  21.  22  and  23.— Cultures  of  .  Ischcrsonia  alcyrodis Plate  I 

Fig.  24.— .Ischcrsonia  flaro-citrina  on  Citrus  leaf Plate  II 

Fig.  23.— .Ischcrsonia  alcyrodis  on  Citrus  leaf Plate  II 

Figs.  26  and  27. — Cultures  of  .  Ischcrsonia  flaro-citrina '. Plato   1 1 1 

Figs.  28,  29  and  30.— Cultures  of  Aschcrsonia  flaro-citrina Plate  IV 

Fig.  31. — /  'crticillinin  hctcrocladnin  on  Citrus  leaf Plate  IV 

Figs.  32,  33  and  34. — Cultures  of  /  'crticillinin  hctcrocladnin Plate  V 

Fig.  33. — /  'crticiliinin  hctcrocladnin   on   leaf Plate  V 

Fig.   36. — Sphacrostilbc  coccophila   on   .  Ispidiotns  hcdcrac Plate    VI 

Figs.  37  and  38.—Sphacrostilhc  coccophila  on  Mytilasfiis  citricola Plate  VI 

Figs.  39  and  40. — Cultures  of  Microccra  sp Plate  VI 

Fig.  41.— Microccra  sp.  on  Citrus  leaf Platc   yj 

Fig.  42.— Brown  Fungus  on   Citrus  K-af Plate  yjj 

HH.  43. — Super-parasite  on  Aschcrsonia  flaro-citrina Plate    VI  I 


FUNGI  PARASITIC  UPON  ALEYRODES  GITRI. 

BY 

HOWARD  S.  FAWCETT, 
Plant  Pathologist,  Florida  Agricultural  Experiment  Station. 


I.   INTRODUCTION. 

Since  taking  up  the  investigation  of  Citrus  diseases  in  the  fall  of  1905, 
in  connection  with  work  in  the  Florida  Experiment  Station,  the  author  has 
given  considerable  attention  to  the  study  of  the  fungi  parasitic  on  Aleyrodes 
citri  R.  &  H.,  and  on  scale  insects.  Since  the  beginning  of  the  work  three 
species  of  fungi  have  been  discovered  to  be  parasitic  upon  the  larvae  and 
pupae  of  Aleyrodes  citri;  two  of  these,  Aschcrsonia  flavo-citrina,  and  an 
undetermined  species  of  Microcera,  were  first  noticed  by  Prof.  P.  H.  Rolfs, 
and  the  third,  Vcrticillium  hctcrocladum,  by  the  author.  With  the  addition 
of  these  three,  the  number  of  known  fungus  parasites  of  this  insect  is  in- 
creased to  six,  namely: 

1.    Aschcrsonia  alcyrodis  Webber, 

'2.    Aschcrsonia  flavo-citrina  P.  Henn., 

3.  J^crticilliuni  hctcrodadnin  Penz., 

4.  Spkaerostilbe  coccophila  Tul., 
.">.    Microcera  sp., 

(>.    The  sterile  Brown  fungus  of  Webber. 

Cultures  of  all  these  fungi  except  the  Brown  fungus  have  been  grown  in 
the  laboratory  by  the  author.  One  of  these,  Sphaerostilbe  coccophila.,  had 
been  previously  studied  in  pure  cultures  by  P.  H.  Rolfs,  who  published  his 
results  in  Bulletin  41  of  the  Florida  Experiment  Station  under  the  title  of 
"A  Fungus  Disease  of  the  San  Jose  Scale".  For  this  reason  a  further  study 
of  this  fungus  in  cultures  was  not  undertaken,  and  it  is,  moreover,  only 
rarely  parasitic  upon  Aleyrodes  citri. 

It  is  the  purpose  of  this  thesis,  after  a  brief  review  of  previous  investiga- 
tions of  the  fungus  parasites  of  insects,  to  describe  the  results  of  recent  study 
of  the  fungi  that  are  parasitic  upon  Aleyrodes  citri  in  Florida.  With  the 
description  of  each  fungus  there  is  given  its  distribution  and  the  names  of 
its  insect  hosts.  A  bibliography  of  the  six  fungi  is  added.  The  illustrations, 
except  Figs.  1,  2,  and  42,  are  original.  Technical  descriptions  and  a  general 
review  of  previous  literature,  when  any  such  has  been  published,  are  in- 
cluded with  the  account  of  each  fungus. 

ENTOMOGENOUS   FUNGI. 

The  fact  that  certain  low  forms  of  plant  growth,  such  as  fungi  and 
bacteria,  are  at  times  the  cause  of  the  destruction  of  great  numbers  of 
insects,  has  created  much  popular  as  well  as  scientific  interest  for  many 


G  l-r.\V.l    PARASITIC  UPON  ALKYRODKS  CITRI. 

years.  As  early  as  1T54,  according  to  M.  C.  Cooke,1  a  popular  description 
was  written  by  Father  Torrubia  of  a  fungus  growing  out  from  the  bodies 
of  wasps.  Father  Torrubia  had  collected  specimens  of  this  at  Havana, 
Cuba,  as  early  as  1749.  Cooke  thinks  that  this  fungus  was  Cordyceps 
specocephala.  lie  quotes  Torrubia's  account  from  Edwards'  "Gleanings 
in  Xatural  History,"  published  in  1<5S,  and  says  that  this  species  represents 
the  rather  celebrated  vegetable  wasp  which  had  a  romantic  history  a  century 
l.efore.  Cooke  also  gives  an  account  of  a  species  of  Isaria,  which  had  been 
known  as  early  as  1782  on  the  Sphinx  moth.1  He  mentions  as  many  as 
1!»7  species,  representing  39  genera  of  fungi,  that  have  been  found  growing 
upon  various  insects.  The  majority  of  these  species  are  included  by  Cooke 
under  ."i  genera:  Cordyceps,  with  48  species;  Laboulbenia,  with  34  species; 
Isaria,  with  2\  species;  Entomophthora,  with  22  species;  and  Empusa,  with 
13  species.  Since  then  main  new  genera  have  been  added  to  the  ento- 
inngencms  fungi.  Species  of  Cordyceps  found  on  wasps,  bees,  ants,  cater- 
pillars, and  scale  insects,  have  been  mentioned  by  many  scientists  and 
popular  writers  from  the  last-mentioned  date  down  to  the  present  time. 
Cooke  refers  to  the  "History  of  Insects"  by  Murray,  published  in  1838.  as 
containing  interesting  accounts  of  fungi  growing  upon  insects. 

The  Tulasne  brothers  were  probably  among  the  first  to  study  the  para- 
sitism of  these  fungi.  They  published  descriptions  of  some  of  them  in 
L857,a  and  of  others  in  isii.").-'  Among  those  described  in  1865  was  Sphaer- 
ostilbc  cticcophila  Tul..  which  is  one  of  the  species  treated  of  in  this  thesis 
as  sometimes  parasitic  on  Alcyrodcs  citri.  The  work  of  Pasteur  on  the 
flacherie  of  the  silkworm,  marked  a  great  advance  in  our  knowledge  of 
insect  diseases.  This  disease  was  due  to  a  species  of  bacterium.  Pasteur's 
work  was  taken  up  with  the  view  of  protecting  the  insect  from  parasitic 
growth,  while  most  subsequent  work  has  been  carried  on  with  the  view  of 
destroying  insect  pests  by  means  of  their  parasites.  A  work  of  much  scien- 
tific importance  was  that  of  Roland  Thaxtcr,::  "The  Entomophthoraceae  of 
the  I'nited  States",  published  in  1888.  The  genera  which  he  studied  attack 
flies,  beetles,  moths,  caterpillars,  grasshoppers,  and  plant  lice. 

Since  the  institution  of  Experiment  Stations  in  the  United  States,  ex- 
periments have  been  made  with  several  species  of  fungi,  with  a  view  of 
using  them  in  combating  insect  pests.  l"p  to  this  time  the  greatest  degree 
of  Miccess  has  l;een  attained  in  Florida,  where  the  conditions  of  temperature 
and  moisture  are  conducive  io  the  spread  of  fungi.  The  use  of  fungi  to 
combat  insect  peMs  has  met  with  only  limited  success  in  the  Northern  States. 
A  number  <>f  years  agn  the  employment  of  a  species  of  Sporotrichum  for 
spreading  disease  among  chinch-bugs  received  much  attention.  Tn  1895. 

'Vegetable  Wa>p>  and   Plant  Worm-.  pp.  U-48,  London.   ls«.»:.». 

2Cookr.   M.  C'      \Ym-ialili-   Waspv  and    IMant    Worms.  ,,],.  ;,,  :;;;     n     73    <,<;     j  |-»     ]s-.    ,  n(> 

881. 
'Mi-moil-*  of  tin-  P,.,MOH  Soi-irtv  of  Natural   History.  Vol.  IV.  Xo.  6. 


INTRODUCTION.  7 

S.  A.  Forbes4  of  the  Illinois  Experiment  Station  gave  a  detailed  account  of 
cultures  and  infection  experiments  carried  on  with  this  fungus.  A  few 
sentences  from  his  discussion  of  the  results  are  here  quoted: 

The  white  muscadine  will  not  spread  among  vigorous  chinch-bugs  in  the  field  in 
very  clrv  weather  to  an  extent  to  give  this  disease  any  practical  value  as  a  means  of 
promptly  arresting  serious  chinch-hug  injury  under  such  conditions.  : 

It  is  most  likely  to  catch  in  low  spots,  where  the  soil  is  kept  somewhat  moist  by 
dense  vegetation,  a  mat  of  fallen  herbage,  or  the  like.  *  *  * 

If  decidedly  wet  weather  follows  upon  its  introduction,  even  after  an  interval  of 
several  weeks,  it  is  likely  to  start  up  and  take  visible  effect ;  but  continuous  rains, 
depressing  the  vital  energies  of  the  insect,  seem  commonly  requisite  to  its  efficient 
action. 

Some  investigation  has  been  carried  on  with  a  number  of  other  ento- 
mogenous  fungi  grown  in  pure  cultures.  G.  F.  Atkinson5  and  R.  H.  Pettit6 
studied  cultures  of  Cordyceps,  Isaria  and  Sporotrichuin.  R.  H.  Pettit  in 
his  bulletin  issued  in  1895  included  a  long  bibliography  of  the  literature  on 
entomogenous  fungi,  to  which  any  one  interested  in  the  history  of  this 
subject  is  referred. 

In  1897,  P.  H.  Rolfs,7  in  his  bulletin  "A  Disease  of  the  San  Jose  Scale," 
demonstrated  that  the  fungus  Sphaerostilbc  coccophila  could  be  used  in  a 
practical  way  in  combating  the  San  Jose  scale  in  Florida.  In  1906,  a  valu- 
able paper  by  J.  Parkin,8  "Fungi  Parasitic  on  Scale  Insects,"  gave  a  general 
review  and  the  distribution  of  the  fungus  parasites  of  Coccidae  and  Aley- 
rodidae  which  had  been  described  in  all  countries  up  to  that  time.  He 
referred  to  a  recent  publication  by  Gueguen9  in  France,  which  is  said  to  be 
an  exhaustive  work  on  the  fungus  parasites  of  man  and  animals.  A  recent 
contribution  by  Dop1"  on  a  new  fungus  parasite  in  Martinique  that  has 
saved  the  cocoanut  industry  of  that  island  is  also  briefly  mentioned. 

In  Florida,  insects  belonging  to  the  orders  Coccidae  and  Aleyrodidae 
are  very  subject  to  attacks  of  fungi.  In  addition  to  the  six  fungus  parasites 
of  Alcyrodcs  citri  here  treated  of,  there  are  two  other  fungi  which  are  not 
found  on  this  insect,  although  they  are  quite  common  on  scale  insects  of 
Citrus.  These  are  Ophioucctria  coccicola  E.  &  E.,  and  Myriangiuw  duriaci 
Mont,  both  of  which  are  illustrated  in  Bulletin  94  of  the  Florida  Experi- 
ment Station.  Webber  also  found  on  the  wax  scale  Ceroplastcs  florldcns'is, 
the  fungus  Aschcrsoma  turbinata;  and  he  mentions  finding  on  various  in- 


4  Experiments  with  the  Muscadine  Disease  of  the  Chinch-bug,  etc.,  111.  Agr.  Exp.  Sta., 

Ikil.  :;s,  1S95. 

5  Artificial  cultures  of  an  Entomogenous  Fungus.    Bot.  Gaz.,  Vol.  XIX,  pp.  129-145,  1894. 
h  Studies  in  Artificial  Cultures  of  Entomogenous  Fungi.    Cornell  Univ.  Agr.  Exp.  Sta. 

Bui.  97,  1S95. 

7  A  Fungus  Disease  of  the  San  Jose  Scale.    Fla.  Agr.  Exp.  Sta.  Bui.  41,  1897. 

8  Annals  of  Roy.  Bot.  Card.  Peradeniya,  Vol.  3,  Part  1. 

9  Gueguen,  F.  Les  Champignons  parasites  de  I'homme  et  des  animaux,  pp.  252,  Paris, 

1904.    Bot.  Centralbl.,  XCVI,  p.  044. 

"  Dop,  P.  Bull.  Sci.  France  et  Belgique.  XXXIX,  p.  1P>5,  1905.    Bot.  Centralbl.,  XCIX, 
p.  50.*). 


>  I-l'Ni'.I    PARASITIC    UPON    ALEYRODES   CITRI. 

sects  other  Aschersonias,  which,  as  far  as  we  know,  he  has  not  identified. 
I'mf.  II.  II.  Hume  sent  to  the  author  in  1906  a  species  of  Aschcrsonia  found 
mi  what  appeared  to  he  an  Alcyrodcs  on  the  leaves  of  Hc.v  Dahoon.  It  is 
(|iiite  probable  that  further  observation  will  reveal  a  number  of  other  species 
»>f  fungi  parasitic  u])nn  insects  of  these  two  orders  in  Florida  and  the  ad- 
joining S:au--. 

AI.KYKDDES   CITRI. 

ffhis  insect,  the  larval  and  pupal  stages  of  which  are  parasitized  by  the 
fungi  to  he  discussed  later,  has  been  a  serious  pest  of  orange  groves  in 
Florida  and  the  adjoining  States  for  a  number  of  years.  It  had  been  ob- 
served by  C.  Y.  Riley  in  1878  in  the  greenhouses  at  the  United  States  De- 
partment of  Agriculture  at  Washington.  In  1885,  Mr.  Ashmead  wrote  an 
account  of  it  for  the  "Florida  Despatch",  in  which  he  gave  it  the  name  of 
Alc\rodcs  citri.  In  1895,  Riley  and  Howard11  first  described  this  species 
in  "Insect  Life".  In  this  publication  it  is  reported  as  having  been  received 
from  Mississippi.  Louisiana,  North  Carolina  and  many  points  in  Florida, 
(xainesville  and  Crescent  City  are  places  mentioned  at  which  it  had  been 
studied  by  Jas.  Yoyle  and  H.  G.  Hubbard,  before  1893.  It  is  also  stated  that 
during  the  years  1892  and  189;?  it  had  so  multiplied  in  parts  of  Louisiana  and 
Florida  as  to  deserve  immediate  attention.  It  is  of  interest  here  to  note  that 
it  was  about  this  time.  IS!):?,  that  Webber  discovered  the  first  fungus  para- 
site of  this  insect. 

This  insect  is  not  a  true  fly,  as  the  name  might  imply,  but  belongs  to 
the  Order  I  lemiptera,  which  also  includes  the  plant  lice  and  scale  insects. 
Tlie  following  summary  of  the  life-history  of  Aleyrodes  citri  is  from  Bul- 
letin ss  nf  the  Florida  Agricultural  Experiment  Station,  by  E.  W.  Berger : 
There  are  three  well-defined  broods  of  the  whitefly,  with  an  interval  of  several 
da\s  t..  several  weeks  hetweeii  each  brood,  when  few  or  none  are  seen  on  the  wing. 
The  first  brood  generally  appears  some  time  during  March,  April  or  May;  the  second 
during  June.  Jul\  or  August;  and  the  third  during  September  and  October. 

Larvae  and  pupae  of  the  whitelly  are  to  be  found  on  the  under  surfaces  of  the 
leave-,  and  seldom  elsewhere.  The  larvae  are  scale-like  and  closely  appressed  against 
tile  leaf.  They  vary  in  si/e  from  the  very  young,  just  visible  to  the  unaided  eye,  to  the 
fully  matured  larvae  which  measure  about  one-sixteenth  of  an  inch  in  length. 

The  larvae  are  white  and  translucent  with  a  tinge  of  yellow,  and  almost  invisible 

upon  the  leal.     The  pupa    (Fig.  :».   X...  s)   is  the  transformation  stage  from  the  larva 

to  the  adult  winged  tly.     The  pupae  are  readily  visible  as  yellowish-white,  plump,  oval 

b-,di,.^with  a  dark  reddish  sp.,t  on  the  back.    From  the  pupa  emerges  the  adult  winged 

Tin-   little   white  cases,   with   a  T-shaped  split  on  the  back,   found  on   the   under 

;  a  leal,  are  tin-  empty  pupa  cases  from  which  the  adults  have  emerged  (Fig. 

No,   in).     The  eggs   <Fi«.    ,.   N08,  3  and  ft)   are  JUS1   visible  to  the  unaided  eye  as  a 
upon   the   nndrr   surface   ,,f   ,he   leaves.     An   ordinary   hand    lens    will    show 
them  as  little  egf-shaped  bodies  iniu-h  resembling  grains  of  wheat.     *     *     * 


Fig.    1. — AlJvYRODES    CITRI.* 

No.   1   and  2,  Adult  female;  No.  :-i.   Egg;   No.  4,  Egg-shell;   No.  5,  Claspers  at  tip  of 
abdomen  of  male;  No.  6,  Antenna;  No.  7,  Fore  margin  of  front  wing. 

INSECTS  SOMETIMES  MISTAKEN  FOR  ALEYRODES  CITRI. 

No.  8,  Larva  of  Alcyrodcs  floridcnsis;  Nos.  <)  and  10,  Margin  of  larva;  No.  11,  Larva 
of  Lccaniuin  hesperidum. 


From  Fla.  Agr.  Exp.  Sta.  Bui.  07,  by  H.  A.  Gossard. 


Fig.  2.— ALEYRODES  CITRI.* 

No*.  1  and  :->.  Larva  first  stage,  at  different  magnification* ;  No.  3,  Larva,  second  stage  - 
No.  4.  Larva  third  stage;  No.  5,  Larva,  fourth  stage;  No.  .;.  Margin  of  advanced 
larva;  No.  7,  Vasiform  orifice  of  fourth  stage;  Xo.  s,  Pupa;  No.  0,  Adult  emenrine 
tn.ni  pupa-case;  No.  10,  Empty  pupa-case. 

*From  Fla.  Ayr.  Kxp.  Sta.  I'.ul.  c,7,  by  H.  A.  Gossard. 


INTRODUCTION.  9 

Twenty  thousand  eggs  have  been  estimated  on  a  large  orange  leaf.  From  observa- 
tions made  in  the  laboratory,  egg-laying  begins  when  the  female  is  from  eighteen  to 
thirty  hours  old ;  and  from  seventeen  to  twenty-five  eggs  are  deposited.  These  eggs 
are  generally  all  laid  within  twenty-four  hours  after  the  first  egg  has__h£en  laid.  Her 
length  of  life  has  been  estimated  at  from  three  days  in  warm  weather  to  three  weeks 
in  cool  weather,  and  the  complete  length  of  life  cycle  from  egg  to  adult  is  from  forty 
or  fifty  days  in  summer  to  six  months  in  winter. 

The  origin  of  the  whitefly  pest  in  Florida  is  only  a  matter  of  con- 
jecture. It  is  not  definitely  known  whether  it  is  a  native  species  or  was 
introduced  from  the  East.  A  recent  report  that  Aleyrodes  citri  has  been 
discovered  in  Asia  gives  some  weight  to  the  latter  view.  H.  A.  Gossard, 
in  Bulletin  (>T  of  the  Florida  Experiment  Station,  "The  Whitefly",  1903,  said 
with  regard  to  its  advent  in  Florida : 

The  fly  seems  to  have  been  first  known  in  Florida  throughout  the  region  comprised 
in  Volusia,  Marion,  Lake,  Alachua,  and  Orange  counties ;  from  which,  I  have  little 
doubt,  it  was  transferred  to  Manatee  county  and  to  local  centers  along  the  northern 
borders  of  the  State. 

It  had  therefore  become  widely  distributed  before  it  attracted  any  consid- 
erable attention.  At  the  present  time  it  is  widely  distributed  in  many  parts 
of  Florida,  and  is  spreading  slowly  to  parts  not  before  infested,  in  spite  of 
the  work  that  is  done  by  the  growers  to  keep  it  out  of  the  groves. 

Several  investigations  are  being  carried  on  at  the  present  time  by  the 
Florida  Experiment  Station,  and  by  the  United  States  Department  of  Agri- 
culture in  order  to  work  out  practical  methods  of  controlling  the  pest. 
Spraying  with  insecticides,  fumigation  with  hydrocyanic  acid  gas  under 
tents,  and  infection  with  fungus  parasites  have  all  been  used.  Fumigation 
and  fungus  infection  are  the  most  promising  remedies  known  at  the  present 
time.  The  use  of  the  fungus  parasites  in  destroying  this  insect  will  be 
briefly  discussed  later,  when  the  various  fungi  are  described. 

The  most  serious  injury  caused  by  the  whitefly  is  the  sooty  mold  that 
always  follows  the  insect.  This  is  a  species  of  Meliola,  a  soot-colored 
fungus  that  lives  in  the  honeydew  secreted  by  the  whitefly  larvae.  Since 
the  larvae  are  found  upon  the  under  surfaces  of  the  leaves,  the  honeydew 
collects  upon  the  upper  surfaces  of  the  leaves  below  and  furnishes  a  suita- 
ble medium  for  the  growth  of  Meliola.  The  sooty  mold  spreads  in  a  black 
layer  over  the  surface.  The  fruit  is  also  blackened,  so  that  it  must  frequently 
be  washed  before  it  is  shipped.  The  vitality  of  the  tree  is  lowered,  not 
only  by  the  loss  of  the  nourishment  sucked  out  by  the  insects,  but  also  by 
the  shutting  off  of  the  sunlight  from  the  surfaces  of  the  leaves.  An  account 
of  this  fungus  is  given  by  Webber  in  Bulletin  13  of  the  Division  of  Vegetable 
Physiology  and  Pathology,  Washington,  D.  C. 


10  FUNGI   PARASITIC    1'1'ON    AI.KYKODKS  CITRI. 

II.   ASCHERSONIA  ALEYRODIS  WEBBER. 

This  species  was  first  discovered  by  H.  J.  Webber  in  August,  18913,  at 
Crescent  City,  in  the  grove  of  J.  H.  Harp.  Mr.  Webber12  published  a  pre- 
liminary notice  of  the  entomogenous  nature  of  this  fungus  in  1894,  referring 
it  to  Aschcrsonia  tahitcnsis  Mont.  In  189(5,  under  the  same  name,  he 
mentions  it  in  the  bulletin,  "The  Principal  Diseases  of  Citrus  Fruits  in 
Florida". 1:I  Finding  it  after  further  study  to  be  a  distinct  species,  he  de- 
scribed it  in  1897  in  his  bulletin,  "Sooty  Mold  of  the  Orange  and  its  Treat- 
ment," as  Aschcrsonia  alcyrodis,'14  as  follows: 

.Ischcrsonia  alcyrodis  Webber.  Stroma  hypophyllous,  depressed  hemispherical, 
pinkish  buff  or  cream  colored,  coriaceous,  1 — 2V£mm.  in  diameter ;  mycelial  hypothallus 
grayish  white,  forming  a  thin  membrane  closely  adhering  to  the  leaf  and  extending 
about  1  mm.  beyond  the  stroma ;  perithecia  membranaceons,  at  first  superficial,  later 
becoming  immersed,  irregular,  reniform  or  orbicular  in  mature  specimens,  and  opening 
by  small,  round,  or  elliptical  pores  or  slits;  basidia  crowded,  filiform,  slender,  con- 
tinuous, 28 — 40  microns  long,  0.94 — 1.5  in  diameter;  paraphyses  abundant,  slender, 
projecting  beyond  the  basidia,  65 — 100  microns  long,  y± — 1  micron  in  diameter;  spor- 
ules  fusiform,  continuous,  mucilaginous,  hyaline,  sometimes  obscurely  3 — 4  guttulate, 
9.4 — 14.1  microns  long  by  0.94 — 1.88  microns  wide,  very  abundant  and  erumpent,  form- 
ing conspicuous  coral  red  or  rufus  masses.  (Parasitic  on  Alcyrodcs  citri  R.  &  H.  infest- 
ing citrous  leaves  in  Florida). 

HISTORY. 

Some  species  of  Aschersonia  have  been  reported  to  be  conidial  stages  of 
the  genus  Hypocrella,  an  Ascomycete.  Massee13  speaks  of  having  shown 
that  the  ascigerous  forms  of  species  of  Aschersonia  were  produced  on  fallen 
leaves  on  which  the  conidial  stages  had  grown.  Parkin10  also  mentions  this 
genus  as  the  probable  perfect  stages  of  species  of  Aschersonia  and  refers 
to  a  species  of  Hypocrella  (H.  Raciborskii)  described  by  Zimmerman,17 
with  a  conidial  stage  referable  to  Aschersonia.  No  ascigerous  forms  have 
as  yet  been  discovered  in  connection  with  the  Aschersonias  in  Florida. 

In  I'.KI."),  F.  S.  Earlels  reported  Aschcrsonia  alcyrodis  on  Alc\rodes 
citri  in  Cuba.  In  I'.MM;.  J.  Parkin10  reported  finding  an  Aschersonia  on  sev- 
eral undetermined  species  of  Aleyrodes  in  Ceylon,  which  closely  resembled 
Aschcrsonia  alcyrodis.  He  said,  "Numerous  forms  of  Aschersonia  have 
been  found  in  Ceylon  on  species  of  Aleyrodes  and  Lecanium".  In  February, 
I'.Kis.  Cook  and  Home20  reported  Aschcrsonia  alcvrodis  on  .llcvrodcs  citri 
and  on  Ale\rodes  howardi'i,  in  Cuba. 


"Webber,  H.  J.  Journal  of  Mycology,  V<>1.  VI,  No.  4,  p.  :;<;:;.  \ 

13  WeblK-r,  II.  J.    Div.  of  Veg.  Phys.  &  Path.,  Bui.  s,  p.  ;_>;.  Washington    I)    C     L896 
"Webber,  H.  J.    Div.  ,,f  YY-.  Phys.  &  Path..  I'.ul.  L3,  p.  21,  Washington    I")   C*.    ls«»7 
"Massee,  G.  Jour.  Hot.  V«>1.  34,  i».  151. 
10  Parkin,  J.   Ann.  Roy.    Bot.  Card.  IVradtniya.  V.>1.  III.  Part  1    pp   »<)  and  3>    I'.MII, 

17  Zimmerman.    Central!),  fiir  I'.akt..  Abth.  II.  Vol.  VII.  p.  872. 

18  Primer  Informe  Anual  de  la  Estarion   Central    . \-ronoinica   <lr   Cuba     1WM    and    l')<r> 

p.   169,   I'.ioii. 

"Annals  Roy.  Bot.  Card.   P<  radnm  a.  Vol.   III.   Pan    I.  p.  ;;«;.   l<t<m. 
"Cook,  M.  'l\.  and  llornr.  \\'.  T.    Cuban  K\p.  Sta.    P.nl.  (.i.  p.  :;l.    1908. 


ASCHERSONIA   AIvEYRODIS.  11 

Previous  to  Webber's  publication,21  the  entomogenous  nature  of  the 
genus  Aschersonia  was  not  known,  although  up  to  that  time__there  were  19 
species  of  this  genus  described,  as  recorded  in  Saccardo's  "Sylloge  Fun- 
gorum".  This  species  was  therefore  the  first  known  parasite  of  Aleyrodes 
citri,  and  was  probably  the  first  fungus  that  had  been  reported  on  any 
species  of  Aleyrodes.  In  the  course  of  his  investigations  on  the  sooty  mold, 
Webber  reported  that  he  had  found  three  other  species  of  Aschersonia, 
parasitic  on  other  insects  in  Florida ;  one  of  which  was  Aschersonia  tur- 
binata  on  the  Wax  Scale  (Ceroplastes  floridensis  Comst.).  The  others 
were  not  determined  by  him.  In  1897,  when  he  wrote  his  bulletin  on  sooty 
mold,  Webber  reported  that  Aschersonia  aleyrodis  was  found  in  Florida 
at  Crescent  City,  Bartow,  Panasoffkee  and  Gainesville.  He  also  stated  that 
no  sign  of  the  fungus  was  apparent  in  groves  infested  with  Aleyrodes  citri 
at  Ocala,  Orlando,  Evinston  and  Ormond.  In  the  same  bulletin,  the  de- 
velopment of  the  fungus,  the  probable  method  of  spore  dissemination,  and 
the  methods  of  introducing  the  fungus  on  the  orange  trees,  are  discussed 
at  some  length.  The  description  of  the  development  of  the  fungus  in  the 
next  paragraph  is  taken  with  slight  changes  from  this  bulletin.22 

The  first  indication  of  the  effect  of  the  fungus  on  the  larva  of  the  whitefly  is 
the  appearance  of  slightly  opaque,  yellowish  spots  unusually  near  the  edge  of  the 
larva.  In  the  early  stages  of  infection  the  larva  becomes  noticeably  swollen,  and  appears 
to  secrete  a  greater  abundance  of  honeydew  than  normally.  As  the  fungus  develops, 
the  interior  organs  of  the  larva  appear  to  contract  away  from  the  margin,  leaving  a 
narrow  circle,  which  becomes  rilled  with  hyphae.  Shortly  after  this  the  hyphae  burst 
out  around  the  edge,  forming  a  dense  marginal  fringe.  This  may  form  all  around 
the  larva  at  about  the  same  time,  or  develop  at  one  portion  of  the  margin  sooner  than 
the  others.  Death  usually  ensues,  it  is  believed,  before  the  hyphae  burst  out.  Tne 
fungus  does  not  spread  over  the  leaf  to  any  extent,  but  grows  upward  in  a  mass, 
gradually  spreading  over  the  larval  scale.  It  is  not  uncommon  to  find  the  pycnidia,  with 
their  bright  coral-red  masses  of  sporules,  formed  in  a  circle  around  the  edge  of  the 
larva  while  it  is  yet  visible.  As  the  Aschersonia  develops,  the  hyphae  spread  over 
the  larva  forming  a  dense  compact  stroma,  which  ultimately  entirely  envelops  the 
larva.  The  stroma  in  this  stage  is  thin  and  disk-like,  the  fructification  being  usually 
borne  in  a  circle  near  the  edge.  The  hyphae,  which  make  up  the  main  mass  of  the 
stroma  are  from  8.5  to  7.5  micro-millimeters  in  diameter.  Within  the  body  of  the 
insect  and  near  the  pycnidia  they  are  somewhat  smaller. 

METHODS  OF  INTRODUCTION. 

Two  methods  of  introducing  the  fungus  into  groves  infested  with 
Aleyrodes  citri  were  used  by  Webber  with  fair  success.  (1)  Pinning 
fungus-bearing  leaves  into  trees  infested  with  Ale\rodes  citri,  in  such  a 
way  as  to  cause  the  fungus  spores  to  come  in  contact  with  larvae  not  yet 
infected.  (2)  Planting  small  trees  with  fungus  infected  larvae  in  a  grove, 
so  that  the  fungus-bearing  leaves  came  in  contact  with  the  leaves  on  which 


21  Webber,  H.  J.    Div.  of  Veg.  Phys.  &  Path..  Bui.  13,  p.  20,  Washington,  D.  C.,  1897. 
"Webber,   H.  J.   Div.  of  Veg.    Phys.   &   Path.,   Bui.    i;$,  pp.  23-24,   Washington,   D.   C, 
1  S<)7 


1\!  i'l'XC.I    PARASITIC    ri'O.N    AI.K.Vkt  >!>KS    CITRI. 

it  was  desired  to  start  the  fungus.  Further  methods  of  introducing  this 
Asclvrsmiia  by  spraying  the  trees  with  water  containing  fungus  spores, 
obtained  either  from  previously  infected  larvae  or  from  artificial  cultures, 
have  been  recently  carried  on  by  E.  W.  Berger2'5  of  the  Florida  Experi- 
ment Station.  Webber24  had  tried  infecting  larvae  by  spraying  a  mixture  of 
conidia  in  water,  but  had  failed  to  reproduce  the  fungus  in  this  way.  E.  W. 
I  Merger  has  found  that  to  succeed  with  this  method  it  is  best  to  have  a  spray 
pump  that  contains  no  copper  parts,  and  that  has  also  not  been  previously 
used  for  spraying  fungicides  or  insecticides.  Fairly  good  infection  of  this 
fungus  has  been  obtained  bv  Merger,  by  the  spore-spraying  method,  at  St. 
Petersburg,  Leesburg.  New  Smyrna,  Gainesville  and  Lake  City.  The  fact 
that  infections  may  be  made  from  cultures  that  have  grown  under  artificial 
conditions  in  the  laboratory  for  long  periods  of  time,  suggests  the  possi- 
bility of  using  these  cultures  in  a  practical  way  at  the  very  beginning  of 
the  rainy  season,  when  fresh  fungus  on  leaves  is  hard  to  obtain.  Consid- 
erable quantities  of  this  fungus  may  be  grown  artificially  on  various  media, 
as  will  be  shown  in  the  following  pages. 

C.Kk.M  I. NATION     OF    CONIDIA. 

Conidia  of  this  fungus  were  germinated  in  hanging  drop  cultures  of  dis- 
tilled water,  tap  water,  and  various  solutions  of  glucose.  In  all  of  these 
cultures  the  germination  was  very  slow,  scarcely  ever  beginning  in  less 
time  than  v?n  hours.  Germination  in  distilled  water  and  tap  water  was  very 
feeble,  while  that  in  solutions  of  glucose  was  much  stronger,  as  is  explained 
more  fully  under  the  germination  tests  for  Aschcrsonia  flaro-citrina. 

Trials  were  made  at  various  times  to  germinate  spores  in  hanging  drop 
cultures  from  pustules  that  had  dried  in  the  atmosphere  of  the  laboratory. 
The  following  is  a  record  of  these  tests: 

/7  1.    On    November    K),    l!)()(i.    cultures   were   made    from 

//  leaves  collected  on  October  IV.    I'.HH;,  which  had  remained 

/I      in  the  laboratory  v»s  days.     The  tests  were  made  in  glucose, 
1 1       in  distilled  water,  and  in  tap  water.     On  December  11   (31 
days)   sporids  formed  in  :»  per  cent,  glucose.     The  growths 
Fit:.:;.  "i   distilled   water  and  in  tap   water  had  not  proceeded  far 

"IIH  SL  -    (  >»  January  5,   1907,  cultures  were  made  from  leaves 


nonn 


collected   October    IV,    lixxi,    which    had    remained    in    the 

laboratory  for  s.~>  days.     The  test  was  made  in  distilled  water.      \o  germina- 
tion   took    place. 


•'  Fl;i.   Kxp.   Sta.   Bui.  88,  ].p.  57-63,    I'.MM;. 

"Webber,  II.  J.    Div.  of  Veg.  Phys,  \-  Path.,  Bui.  13,  p.  :>«;.  Washington,  D.  c. 


ASCHERSONIA   ALEYRODIS.  13 

3.  On  April   18,   1907,  cultures  were  made  in  tap  water   from  leaves 
collected  October  12,  1906,  which  had  remained  in  the  laboratory  189  days. 
No  germination  took  place.  CZlr"::'"  '"•"**^ 

4.  On  April  18,  1907,  cultures  were  made  in  tap  "^""^^S^niX^ 
water  from  leaves  collected  on  December  12,   1906,     Fig.  4.   conidiumof  Ascher- 
which  had  remained  in  the  laboratory  128  days.     No       gftSSSftg^;  SK 
germination  took  place.                                                              tion  at  25°c..  x  1000. 

5.  On  April   18,    1907,  germination  trials  were   made   from   a   culture 
isolated  December  7,  1906,  which  was  transferred  to  potato  on  January  14, 
1907,  and  had  not  entirely  dried  out.    A  few  spores  germinated. 

CULTURES. 

Pure  cultures  of  Aschersonia  aleyrodis  were  first  obtained  in  January, 
1907.  On  December  7,  1906,  petri  dishes  of  neutral  5  per  cent,  glucose  agar 
were  poured.  These  were  made  by  introducing  into  the  melted  agar  a 
platinum  loop,  that  had  been  thrust  several  times  into  a  test-tube  containing 
spores  from  several  stromata  shaken  up  in  sterile  water.  In  the  first  dilu- 
tion, on  January  5  (29  days),  at  a  temperature  of  15°  to  25°  C.,  minute 
fungus  mycelia  appeared,  yellow  in  the  center,  with  a  fringe  of  delicate 
white  hyphae  projecting  outward.  On  January  8  .(32  days),  the  largest 
of  these  had  turned  red  in  color.  They  were  raised,  hemispherical,  and 
had  the  upper  surface  dotted  with  little  white  lumps.  Larger  stromata  were 
2  to  4  mm.  in  diameter.  On  January  15  (39  days)  the  stromata  were  5 
to  7  mm.  broad,  with  a  wide  fringe  of  straight  hyphae  projecting  outward 
over  the  agar.  The  stroma  by  this  time  contained  pycnidial  cavities  with 
spores  (Plate  I,  Fig.  20). 

On  April  10,  1907,  this  fungus  was  again  isolated.  Leaves  were  picked 
at  Orlando,  on  April  6.  Pustules  were  broken  up  in  water  in  a  watch-glass, 
and  a  dilution  set  of  three  petri  dishes  A,  B  and  C,  was  poured  with  agar 
(1  per  cent,  normal  acid  to  phenolphthalein) ,  to  which  5  per  cent,  glucose 
sugar  had  been  added.  Petri  dish  A  was  overrun  with  bacteria  and  quick- 
growing  fungi.  Petri  dish  B  contained,  on  April  26  (16  days),  about  50 
centers  of  growth  just  beginning,  and  a  few  bacteria.  Petri  dish  C,  on 
April  26  (16  days),  contained  no  visible  growth.  On  May  11  (31  days), 
C  contained  a  fine  growth  of  11  mycelia,  which  probably  first  showed  a  few 
clays  before.  No  further  record  was  kept. 

On  September  23,  1907,  this  fungus  was  isolated  for  the  third  time  in 
petri  dish  cultures  A,  B  and  C.  Four  or  five  small  pustules  were  shaken 
up  in  7  cc.  of  water  until  it  became  milky  in  appearance.  Five  loopfuls  wrere 
washed  into  A,  etc.  A  was  contaminated  with  other  fungi,  C  developed  one 
mycelium  of  A.  alcyrodis,  and  one  of  another  fungus.  Petri  dish  B  devel- 
oped a  pure  culture  as  follows: — On  October  8  (15  days),  one  point  of 
growth  was  just  appearing.  On  October  18,  there  were  four  mycelia,  five 
to  six  mm.  in  diameter,  with  rings  of  reddish  pycnidia ;  and  seven  others 
just  starting.  On  October  28  (35  days),  twenty  very  red  pustules  with 
abundant  spores  and  light  gray  fringes  of  outgrowing  hyphae  had  de- 
veloped. 

From  these  isolation  tests,  it  appears  that  on  5-10  per  cent,  glucose  agar 
in  the  laboratory,  it  requires  from  30-40  days  for  the  fungus  to  mature  a 
pustule  and  produce  pycnidia.  This  time  corresponds  somewhat  closely 
to  the  time  for  the  fungus  to  develop  upon  larvae  of  Ale\rodc$  citri,  as 


1  t  l-l   NC.I     I'AKASITIC    fl'UN    Al.KYKODKS    CITRI. 

shown  by  the  infection  experiments  of  K.  \V.  Uerger.  (See  Bulletin  88. 
Florida  Experiment  Station,  pp.  .*>;.  oS.)  The  fungus  is  extremely  slow  in 
developing  in  the  petri  dishes,  thus  increasing  the  liability  to  contamination 
with  other  fungi  and  bacteria.  Its  slow-growing  habit  demands  therefore 
a  strictly  pure  culture,  since  the  rapidly  growing  fungi  and  bacteria  will 
otherwise  crowd  it  out  completely. 

The  many  previous  failures  of  the  author  and  of  others  before  him  to 
grow  this  fungus  in  cultures,  were  probably  due  to  the  fact  that  the  petri 
dishes  were  rejected  too  soon,  or  were  allowed  to  dry  out  before  the  spores 
had  time  to  form  mycelia  and  stromata.  This  fungus  was  transferred  from 
petri  dish  cultures  to  test-tubes  of  sweet  potato  (Plate  I,  Fig.  22),  Irish 
potato,  rice,  white  cornmeal  (Plate  1.  Figs.  21,  <M).  and  bread.  On  all 
of  these  media,  the  growth  was  similar  in  general  appearance  to  the  growth 
of  Aschcrsonia  flat'o-citrina.  except  that  the  color  of  the  stroma  and  spore- 
masses  was  red  instead  of  yellow.  The  most  luxuriant  growth  was  on  sweet 
potato  plugs.  The  characteristic  red  color  of  the  fungus  stroma  rarely  ap- 
peared on  Irish  potatoes.  This  would  seem  to  indicate  that  sugar  was 
necessary  for  the  proper  development  of  both  the  red  pigment  of  Aschcr- 
sonia alcyrodis.  and  the  yellow  pigment  of  A.  flat'o-citrina. 

The  growth  on  sweet  potato  plugs  is  given  here  for  comparison  with 
the  growth  of  Aschersonia  flaVD-citrina  on  this  same  medium. 

1.  ( )n  April  <s.  1JM)?,  spores  were  transferred  from  cultures  made  on 
January  14,  1907.  The  spores  were  streaked  onto  the  surface  of  the  sweet 
potato  plug  with  a  platinum  needle.  On  April  17,  abundant  growth  all 
along  the  streak  had  begun.  ( )n  April  2(>,  a  large  raised  red  mass,  40  mm. 
long,  had  formed. 

8.  <  )n  April  s.  spores  were  transferred  as  in  Xo.  1.  On  April  17,  very 
abundant  growth  had  started,  and  on  April  2(>,  a  very  large  red  mass  had 
formed. 

.">.  (  )n  April  s.  spores  were  transferred  as  in  Xo.  1.  On  April  17,  good 
growth  with  thickened  points  had  started.  ( )n  April  2<>.  a  very  large  mass 
of  red  growth  had  formed. 

I.  (  >n  April  S.  spores  were  transferred  as  in  Xo.  1.  On  April  17.  a 
cream-colored  to  orange,  mealy  appearance  was  evident,  spreading  to  each 
side  of  the  streak.  (  )n  April  2<>,  an  abundant  growth,  red  in  color,  had 
formed. 

KXI'KKIMKNTS     IN     C.KOWI.XC.    AsC 1 1  KKSo\  I  A     AI.KYRODI  S     IN     I.AKC.I-.    <J  t  'A  N  TIT  I I-S. 

In  April,  r.ni;.  experiments  were  begun  in  order  to  grow  large  quantities 
of  fungus  for  infection  of  Alc\rodcs  citri.  Ten  large  moist  chambers,  nine 
wide-nKHlthed  bottles  of  .V><>  cc.  capacity,  and  four  petri  dishes  five  inches 
in  diameter,  wen.-  prepared  with  sweet  potato  medium.  The  potatoes  were 
washed,  peeled,  washed  again  and  put  through  a  meat  chopper.  This 
ground-up  ma.ss  was  then  washed  in  running  water  to  get  out  tine  particles. 
and  the  moist  medium  was  sterilized  in  the  autoclave  at  110°  C.  for  about 
20  minuu-s.  After  .sterili/ation.  the  medium  appeared  well  cooked. 

(  )n  April  '».  these  were  inoculated,  in  the  transfer  closet,  by  spraying  the 
>urfaiv  of  the  medium  with  a  hand  atoini/cr  with  a  mixture  of  conidia  in 


ASCHKRSONIA  ALEYRODIS.  15 

sterile  water.  The  conidia  were  obtained  from  an  old  culture  of  the  fungus 
grown  on  sweet  potato.  All  of  the  cultures,  except  two  large  petri  dishes, 
finally  became  contaminated  with  a  growth  of  bacteria.  This-was  probably 
due  to  insufficient  sterilization  of  the  interiors  of  the  large  masses  of  medium 
:n  the  moist  chambers  and  in  the  500  cc.  bottles.  The  fungus  in  the  two 
petri  dishes  which  were  successful,  appeared  in  15  days  as  a  creamy  white, 
ieit-like  growth  over  the  surface  of  the  medium,  with  no  red  color.  Very 
little  red  color  appeared  later,  and  no  large  spore-masses  developed.  It 
seemed  that  the  spores  had  been  sown  too  thickly  over  the  surface  to  develop 
the  characteristic  pustules  with  pycnidial  cavities.  This  experiment  was 
practically  a  failure. 

On  June  12,  1907,  five  bottles  of  ground-up  sweet  potato,  and  one  bottle 
of  bread,  which  had  been  sterilized  in  an  autoclave  for  about  half  an  hour 
at  120°  C.,  were  inoculated  by  streaking  the  surface  with  a  large  platinum 
loop  from  cultures  previously  made  on  sweet  potatoes.  Three  of  these 
were  successful,  two  on  sweet  potato,  and  one  on  bread.  The  notes  on 
these  are  as  follows : 

1.  On  June  12,  1907,  a  culture  on  bread  was  made  from  a  culture  on 
sweet  potato  plug,  which  had  been  transferred  three  times  from  an  isolation 
culture  in  petri  dish  poured  December  7,  1906,  and  described  above. 

Transfers  had  been  made  on  January  14,  1907,  April  10,  1907,  and  June 
3,  1907.  On  June  19,  the  fungus  was  growing  well  at  one  point. 

On  July  1,  a  large  raised  mass  */2  inch  in  diameter  was  formed.  On 
July  20,  a  large  area  1  inch  in  diameter,  and  red  in  the  interior,  with  abund- 
ant spores,  had  grown. 

2.  On  June  12,  1907,  a  culture  on  sweet  potato  was  made  from  another 
culture  with  same  history  as  above.     On  June  19,  the  fungus  had  started  at 
seven  points.     On  July  1,  masses  1-3  inch  in  diameter  had  formed  on  one 
side  of  the  bottle. 

3.  On  June  12,  1907,  a  culture  on  sweet  potato  was  made  from  a  sweet 
potato  plug,  which  had  been  transferred  once  from  a  petri  dish  culture  of 
April  10,  1907,  being  transferred  on  June  3,  1907.     On  June  19,  the  fungus 
was  just  starting  at  three  points.     On  July   1,   raised   areas   one   inch   in 
diameter  had  formed  on  one  side.     On  July  20,  a  growth  l/2  inch  in  diam- 
eter had   formed. 

( )n  June  19,  six  bottles  of  sweet  potato  and  one  of  bread  were  inoculated 
from  sweet  potato  test-tube  cultures  which  had  been  transferred  twice  from 
an  isolation  culture  made  not  later  than  April  10,  1907.  Four  bottles  de- 
veloped pure  cultures. 

1.  On  June  19,  1907,  the  surface  of  a  bottle  of  sweet  potato  medium 
was  streaked  with  a  small  needle  from  a  culture  of  June  3,  1907.     On  July 
1,  three  or  four  areas  of  growth  had  appeared.     On  July  20,  a  good  white 
growth  had  formed  all  around  the  base  of  the  potato  plug. 

2.  On  June  19,  1907,  sweet  potato  medium  was  streaked  as  in  No.  1, 
from  a  culture  made  June  3,  1907.     On  July  1,  a  good  growth  had  formed 
on  the  surface,  white  and  lumpy  in  appearance.    On  July  20,  the  growth  had 
formed  all  over  the  surface  of  potato,  and  spores  had  grown  in  the  pycnidia. 
On  August  12,  spores  were  very  abundant. 

3.  On  June  19,  1907,  sweet  potato  medium  was  inoculated  by  shaking 
up  conidia  in  a  test-tube  of  water  and  pouring  it  over  the  plug.     On  July  1, 
very  small  areas  on  side  of  glass  appeared.     On  August  12,  areas  of  large 
size  had  grown,  but  no  conidia  could  be  found. 


1C  Kr.\<,l     PARASITIC    rroN     A  I.KYROl  >KS    ClTRI. 

I.  On  I  une  1!>,  I'.HI;,  bread  medium  was  inoculated  as  the  sweet  potato 
in  No.  :».  with  eonidia  from  a  culture  made  on  June  :>,  1907.  The  old  potato 
plug  from  the  same  culture  was  also  dropped  in.  ( )n  July  1,  a  good  growth 
out  from  old  plug  had  started.  On  July  •><>.  growth  over  nearly  entire 
surface,  reddish  in  patches,  had  formed.  On  August  12,  no  eonidia  could 
l.e  found. 

INI-KCTION    01-     AI.KYKODKS    CITKI     1-ROM     cn.Tl'KKS. 

In    two   localities   in   the    State,   this    fungus    was    started    on    larvae   of 
.-llcvrodcs  citri,  from  cultures  which  had  grown   for  some  time  on  culture 
media  in  the  laboratory.     This  infection  work  was  done  by  E.  W.  Berger 
at  Gainesville  and  St.  Petersburg,  from  cultures  grown  by  the  author. 
The  following  records  are  taken  from  E.   \Y.   Merger's  field  notes: 

1.  . \ugtist  1().  H»OT.  Gainesville.  From  culture  on  sweet  potato  made  June  :>:\. 
having  been  isolated  not  later  than  April  10,  1907.  Culture  mixed  up  in  water  and 
sprayed  with  hand  sprayer  on  under  surface  of  leaves  on  lower  branches  of  an  orange 
tree.  October  6,  no  fungus  found.  On  Xovemher  1(>.  three  pustules  of  fungus  found. 
On  December  :M.  sprinkling  of  pustules  evident.  April  ::.  1!H)S.  quite  a  sprinkling  of 
fungus  pustules  evident. 

:.'.  August  10.  I'.ioT.  Gainesville,  Florida.  From  old  cultures  in  three  test-tubes. 
Age  of  cultures  unknown.  No  start  by  April  :;.  I'.ios. 

::.  August  1.">,  I'.ioT.  St.  Petersburg,  Florida.  From  culture  made  June  !'.»,  on 
bread  in  large  bottles  and  transferred  twice  before  from  cultures  isolated  not  later 
than  April  10.  The  culture  was  washed  to  fine  pulp  in  water  and  strained.  One  and 
a  half  to  two  quarts  of  the  liquid  was  used.  Sprayed  on  the  under  side  of  leaves  with 
a  compressed-air  sprayer.  On  October  :'!!,  quite  a  sprinkling  of  fungus  was  found. 
Some  twigs  had  several  leaves  well  covered  with  pustules,  mainly  on  the  newest 
growth.  On  December  ]().  about  the  same  condition.  On  February  8,  190S,  an  abund- 
ance of  fungus  was  found  on  northwest  side  of  tree,  and  fresh  pustules  were  appearing. 

t.  August  1"».  I'.iOT.  St.  Petersburg,  Florida.  From  culture  on  sweet  potato, 
made  June  1'.i.  I'.iOT.  Culture  washed  to  fine  pulp  and  strained.  Two  quarts  of  solu- 
tion were  sprayed  on  with  compressed-air  hand  sprayer.  On  October  :Z3.  a  good 
sprinkling  of  fungus  was  found  with  some  leaves  well  covered.  P>est  catdi  was  on 
we>t  side,  mainly  on  newer  growth.  On  December  10,  I'.IOT.  pustules  more  mature. 
but  apparently  not  spreading.  On  February  s  I'.ios.  an  abundant  catch  of  fungus  was 
evident. 

5,  August  i:,.  I'.MiT.  St.  Petersburg.  Florida.  From  a  mixture  of  two  cultures, 
one  of  Ascfarsonta  alcyrndis  made  June  I'.i  on  potato  plug  and  transferred  twice 
before;  the  other  of  .  Isi'licrsaiihi  flai'o-citrina  made  May  :»:;.  mi  sweet  potatoes  in  a 
bottle,  and  transferred  twice  before.  Cultures  mixed,  washed  and  strained,  making 
one  gallon  of  the  solution.  On  October  '.':;,  fair  sprinkling  of  the  fungus,  probably 
only  the  red.  mainly  on  newer  growth.  (  )n  December  10.  same,  but  pustules  more 
matured  On  February  8,  I'.-os.  all  red  pustules,  no  yellow  pre-uit. 

<;  August  14.  I'.iOT.  St.  Petersburg.  Florida.  From  culture  made  June  I'.i.  I'.iOT. 
and  transferred  twi.-e  before.  \o  start  by  February  8,  1908. 

\ugust  M.  I'.iOT.  St.  Petersburg.  Florida.  From  culture  made  April  s.  I'.HMi, 
which  had  been  dried  for  two  months.  The  fungus  bad  been  transferred  twice'  before. 
Isolated  from  petri  dish  culture  made  December  T.  I'.ioi;.  \o  start  of  fungus  by  Feb- 
ruarv  .s.  itMis. 


ASCHERSONIA   FLAYO-CITRINA.  17 

DISTRIBUTION  OF  ASCHERSONIA  ALEYRODIS  IN    1908. 

In  Florida  it  has  been  reported  from  or  seen  at  the  following  places, 
occurring  only  on  Aleyrodcs  citri: 

Alva,  Apopka,  Bartow,  Bradentown,  Buckingham,  Citra,  Fort  Myers, 
Gainesville,  Glen  St.  Mary,  Jacksonville,  Lake  City,  Leesburg,  Manatee, 
Mclntosh,  New  Smyrna,  Oneco,  Orlando,  Oviedo,  Palmetto,  Sarasota,  St. 
Petersburg,  St.  Augustine. 

Outside  of  Florida  it  was  reported  by  Cook  and  Home  from  Cuba  on 
Aleyrodcs  citri  R.  &  H.,  and  Aleyrodcs  howardii.  Quaintance ;  from  Java 
by  Kirkaldy  &  Kotinsky,  doubtfully  upon  Aleyrodcs  longicornis  Zehntner; 
from  Brazil  by  the  same  authority,  doubtfully  upon  Aleyrodcs  horridus 
Hempel;  from  Ceylon  by  Parkin  on  various  undetermined  species  of  Aley- 
rodes;  and  from  Jamaica  by  Cockerell  under  the  name  of  Aschcrsonia  tahit- 
ensis  Mont.,  which  is  probably  A.  alcyrodis  Webber. 

III.  ASCHERSONIA  FLAVO-CITRINA  P.  HENN. 

The  discovery  that  Aschcrsonia  flai'o-citrina  P.  Henn.  was  parasitic 
upon  Aleyrodcs  citri  R.  &  H.,  was  made  by  P.  H.  Rolfs25  by  means  of 
specimens  sent  to  him  from  J.  F.  Adams,  Winter  Park,  Fla.,  in  September, 
1906  (Plate  II,  Fig.  24).  Later  in  the  same  year  E.  W.  Berger  found  this 
fungus  effectively  parasitizing  Aleyrodcs  citri  in  several  other  localities  in 
the  eastern  part  of  Florida,  and  since  that  time  he  has  succeeded  in  intro- 
ducing it  into  still  other  localities.  This  fungus  was  first  described  by  P. 
Hennings  in  1902,  as  occurring  on  leaves  of  Psidium  from  the  botanical 
gardens  of  Sao  Paulo,  Brazil.  No  mention  is  made  by  him  of  any  insect 
associated  with  its  presence  on  the  guava  leaf.  This  species  is  described  by 
Hennings26  as  follows : 

Aschcrsonia  flai'o-citrina  P.  Henn.  Stromatibus  carnosis,  hypophyllis,  subdis- 
coideo-pulvinatis  vel  hemisphaerico-depressis,  citrinis,  2 — 2.5  mm.  diameter,  pruinosis, 
superne  ptmctulato-pertusis,  intus  subaurantiis,  subiculo  membranaceo,  flavo ;  pycnidiis 
immersis  oblongis,  paraphysibus  filiformibus,  flexuosis,  hyalinis  140-180X1—1.5  micr., 
continuis;  conidiis  fusoideis,  utrinque  acutis,  continuis,  hyalinis,  12-18X2  micr.;  con- 
idiopboris  brevibus,  hyalinis,  fasciculatis. 

It  was  found  in  the  botanical  garden  of  Sao  Paulo  on  a  leaf  of  Psidium 
sp.,  October,  1901. 

That  Aschcrsonia  flai'o-citrina  may  be  able  to  attack  other  Aleyrodidae 
besides  A.  citri  is  shown  by  the  fact  that  in  June,  1907,  Stene  of  the  Rhode 
Island  College  of  Agriculture,  was  able  to  infect  larvae  of  Aleyrodcs  raf>or- 
arionnn,  on  cucumber  leaves  in  the  greenhouse,  from  material  sent  from 
Florida  by  E.  W.  Berger.27  These  are  the  only  two  species  of  Aleyrodes  on 
which  it  has  yet  been  observed.  It  is  probable,  however,  that  further  ob- 


25  Rolfs,  P.  H.   Fla.  Exp.  Sta.  Kept.,  p.  xvi,  1907. 
'Hennings.  P.    Hedwigia,  Vol.  41,  p.  HOT,  1902. 
21  Berger,  E.  W.    Fla.  Agr.  Exp.  Sta.  Kept.,  p.  xxxiv,  1907. 


18  FUNGI  PARASITIC  UPON   AI.EYRODES  CITRI. 

servations  will  reveal  its  presence  on  other  Aleyrodidae  native  to  the  woods 
of  Florida. 

COMPARISON    OF   ASCHERSONIA    FLAVO-CITRINA    WITH    A.    ALEYRODIS. 

The  two  species  are  very  much  alike  in  their  general  appearance,  and 
also  approach  each  other  closely  in  the  measurements  of  their  structural 
parts.  The  most  evident  distinction  is  in  the  color.  A.  aleyrodis  is  usually 
red  or  pink,  while  A.  flavo-citrina  is  yellow  and  never  contains  any  reddish 
pigment.  The  stromata  of  A.  aleyrodis,  under  similar  conditions,  average 
less  in  diameter,  and  the  pycnidial  cavities  are  usually  more  sunken  than 
in  A.  flavo-citrina.  The  spores  of  A.  aleyrodis  also  average  a  little  smaller 
than  those  of  A.  flavo-citrina.  Measurements  of  Florida  specimens  show 
that  the  spores  of  A.  aleyrodis  are  about  9 — 14X2 — 3  microns,  while  those 
of  A.  flavo-citrina  measure  about  12 — 15X2 — 3  microns.  Cultures  of  these 
two  Aschersonias  on  similar  culture  media,  under  similar  conditions,  showed 
them  to  be  distinct  forms. 

CULTURES. 

Soon  after  the  discovery  of  A.  flavo-citrina  on  Aleyrodcs  citri,  attempts 
were  made  by  the  writer  to  produce  cultures  of  this  fungus  on  ordinary 
culture  media.  Attempts  to  isolate  Aschersonia  aleyrodis  on  neutral  pep- 
tonized  agar  had  been  made  without  success.  The  beneficial  effect  of  the 
addition  of  sugar  on  the  germination  of  the  spores  in  hanging  drops  had 
been  noticed.  On  the  addition  of  10  per  cent,  glucose  to  the  agar,  petri  dish 
cultures  of  A.  flavo-citrina  were  successfully  grown.  The  growth  on  10 
per  cent,  glucose  agar,  poured  on  September  14,  190f>,  at  a  temperature  of 
about  28°  to  30°  C.,  was  as  follows: 

On  October  2  (18  days)  small,  whitish  delicate-fringed  colonies  ap- 
peared, just  visible  to  the  unaided  eye.  On  October  11  (25  days),  a  distinct 
elevated  stroma  had  formed,  waxy  and  pale,  with  a  yellow  center  contain- 
ing pycnidia  with  spores.  Surrounding  this  was  a  white  fringe  of  outgrow- 
ing mycelium.  These  stromata  became  2  to  (>  millimeters  in  diameter,  and 
closely  resembled  the  stromata  growing  naturally  on  leaves  bearing  larvae 
(Plate  III,  Fig.  2G).  Later  cultures  grown  on  the  same  medium  bore 
stromata  2~>  millimeters  in  diameter,  indicating  that  the  size  of  any  individual 
stroma  depends  on  the  amount  of  the  medium  taken,  and  the  length  of  time 
before  it  is  dried  out  (Plate  III,  Fig.  27).  The  fungus  was  then  transferred 
to  test-tubes  containing  other  media.  Cultures  were  obtained  on  sterilized 
SWeel  potato.  Irish  potato,  hread  and  Her.  The  most  luxuriant  growth  was 
obtained  on  sweet  potato  plugs,  this  being  probably  due  to  the  presence  of 
BUgar  in  that  medium  (  I 'late  IV.  Figs.  88,  -.".'  and  30). 

The  progress  of  the  fungus  on  the  various  media  was  as  follows: 
On  sweet  potato  pings,  transferred  from  petri  dish  culture  by  inserting  a 
platinum  needle  into  a  spore  mass,  tin-re  was  no  evident  growth  in  three 
days.  In  six  days,  numerous  small  white  points  appeared  along  the  scratch 
made-  by  the  needle.  In  fourteen  days,  stromata  •>  mm.  in  diameter,  and 
turning  yellow,  were  formed.  In  twenty  days  these  had  heroine  typical 


ASCHERSONIA   FLAVO-ClTRINA.  19 

stromata  with  spores.  In  forty-seven  days,  these  separate  points  had  grown 
together  into  one  waxy,  yellow  mass,  fringed  and  tipped  with  a  white 
velvety  growth  of  vegetative  hyphae,  as  shown  in  the  photograph  (Plate  IV, 
Figs.  28,  29,  30).  Numerous  pycnidial  masses  were  also  present.  On 
Irish  potato  plugs,  the  growth  of  the  fungus,  for  the  first  fourteen  days, 
was  about  the  same  as  on  sweet  potato  plugs.  From  that  time  on,  the 
growth  was  more  feeble,  and  the  yellow  color  rarely 
appeared.  Typical  spore-masses  were  not  so  abund- 
ant. On  sterilized  rice  there  appeared  in  ten  days  a 
slightly  yellow  growth,  not  much  raised  above  the 
surface.  In  eighteen  days,  the  growth  had  spread 
out  considerably  over  the  surface  of  the  rice,  and  the 
color  had  become  a  decided  yellow,  without  present- 
ing any  raised  mass  as  described  for  sweet  and  Irish 
potatoes.  In  thirty-four  days,  there  appeared  small 
whitish  patches  over  the  surface  of  the  yellow 
growth.  On  white  cornmeal,  the  growth  of  the 
Fig.  5.  fungus  was  the  same  as  on  rice.  On  bread,  the 

Hyphae  ofjtroma.          fungus  grew  well  and  formed  yellowish  masses  in 
a  few  weeks. 

GERMINATION  OF  CONIDIA. 

The  germination  of  the  conidia  of  this  fungus  was  very 
slow  as  compared  with  that  of  many  fungi.  In  September, 
190(3,  germination  tests  were  made  of  conidia  placed  in 
hanging  drops  of  distilled  water,  tap  water,  agar,  and 
various  solutions  of  glucose  in  water.  These  were  pre- 

i  1          1      •  r       •  f     i  •         Fig.  6.  Conidia  from 

pared  by  placing  a  number  of  minute  drops  of  the  solution     dried  pustules  of 

. , .        ,  .  Aschersonia  flavo- 

on  each  sterilized  cover  glass,  and  putting  in  them  by  atrina,  x  1000. 
means  of  a  sterile  needle  a  few  conidia  from  fresh  pustules  of  the  fungus. 
These  were  then  placed  in  a  moist  chamber  to  keep  them  from  drying  out. 
In  all  of  these  solutions  some  germination  took  place.  In  distilled  water  and 
tap  water,  the  germination  was  slow  and  feeble,  the  hyphal  tube  not  advanc- 
ing far.  The  addition  of  sugar  appeared  to  increase  germination  up  to  10 
per  cent,  of  sugar.  Above  10  per  cent,  germination  was  retarded,  and  at  30 
per  cent,  only  a  few  spores  were  seen  to  germinate.  In  October,  1907,  part 
of  the  same  test  was  repeated  with  the  same  general  results ;  except  that  in 
this  case  the  conidia  in  5  per  cent,  glucose  solution  appeared  to  germinate 
a  little  more  readily  than  in  10  per  cent,  and  the  conidia  in  30  per  cent,  solu- 
tion refused  to  germinate  at  all.  Parallel  tests  in  part  were  made  with 
conidia  of  Aschersonia  aleyrodis  with  similar  results. 

The  table  below  gives  the  result  of  the  tests  for  Aschersonia  flavo-citrina. 
In  germinating,  the  first  hyphal  tube  usually  pushed  out  just  behind  one  of 
the  acute  ends  of  the  boat-shaped  spore  (Figs.  7,  8  and  9).  The  acute  end, 


l-TNC.I    I'.'.RASITIC    ri'ON    AI.KYRODES   CITRI. 


which  seemed  to  lack  protoplasm,  was  bent  back  in  the  opposite  direction. 

The  hyphal  tube  then  grew  very  slowly, 
and  in  four  days,  in  10  per  cent,  glu- 
cose solution,  began  to  form  sporids 
at  the  distal  ends  (Figs.  8  and  9). 


Fig.  7.  ronidium  of  A*rhi'i:*»ni<i  ,/fmo-cftrftM 
germinal 'ng  in  ::o  per  cent  glucose  solution 
after  27  dats.  (a)  Original  conidium,  (!>} 
spore  like  bodies.  X  1000. 


Fig.  8.  Fig.  9. 

Figs.  8-9.    Conidia  germinating,  (n)  conidium.  (b) 
hyphal  tube,  (c)  sporid,  X  1000. 


ASCHERSOXIA    FLAYO-CITRINA GERMINATION    OF    CONIDIA. 


MEDIUM. 

'.'  I   TO  28    HOURS. 

44  TO  48  HOURS. 

Distilled  water..    . 

No  germination. 

Germination     just     be- 
ginning. 

Tap  water  .... 

X«>  germination. 

Germination     just     be- 

In 6  days  good  germ- 
ination, some  hyphae 

ginning. 

2  or  3  times  longer 
than  the  conidia. 

Glucose  1  per  cent. 

Germination     just     be- 
ginning. 

Fairly     good     germina- 
tion. 

Glucose  2  per  cent. 

Germination     just     be- 
ginning. 

.(Dried  out.) 

Glucose  3  per  cent. 

Germination      advanced 
farther    than    in    2    per 

Very  good   germination 
of  many  conidia. 

Glucose  5  per  cent  Good  germination  in  :>* 
hours,    hyphal   tubes   as 
long  as  conidia. 

Good  germination,  hy- 
phae  growing  slowly. 

GlucoM-  in  per  cent. 

Very  good  germination, 
hyphal  tubes  2  to  3  times 
length  of  conidia. 

Very  good  germination, 
hyphae  growing  slowly. 

In  4  days  sporids  form- 
ing on  ends  of  hyphal 
tubes. 

Glucose  20  per  cent. 

Only  a  few  just  begin- 
ning to  germinate. 

1  lyphal  tubes  as  long  as 
conidia. 

GlucnM-  :;n  ,,,-r  rent. 

No  germination. 

No  germination. 

A  very  few  finally 
germinated.  S  p  o  r  ids 
formed  in  27  days. 

(  M-rminatinn  tests  of  conidia  fn.ni  dried  pustules  made  at  various  times 
showed  the  following  results: 

1.  (  )n  November  1".  iwii.  lian^in^  drop  cultures  were  made  from 
specimens  sent  in  from  Winter  I 'ark  on  September  -'S,  1  !HX;,  which  had 
remained  in  the  laboratory  exposed  to  the  atmosphere  for  1C.  (lavs.  Tests 


VKRTICILUUM    HETEROCIvADUM.  21 

were  made  in  distilled  water,  in  tap  water  and  in  5  per  cent,  glucose  at  a 
temperature  of  15°  to  20°  C.  No  germination  occurred  up  to  December 
11,  1906,  when  the  slides  were  discarded. 

'2.  On  January  5,  1907,  hanging  drop  cultures  of  conidia  in  distilled 
water  were  made  from  leaves  picked  September  28,  1906,  which  had  re- 
mained in  the  laboratory  exposed  to  the  atmosphere  for  68  days.  No  germ- 
ination was  noticed  up  to  January  9,  1907,  when  the  slides  were  discarded. 

3.  On  January  5,  1907,  hanging  drop  cultures  in  tap  water  were  made 
from  leaves  collected  by  E.  W.  Berger  on  December  18,  1906,  and  kept  in 
the  laboratory  18  days.     On  January  7,  many  conidia  had  germinated,  and 
on  January  I),  some  hyphal  tubes  were  twice  as  long  as  the  conidia. 

4.  ( )n  April  18,  hanging  drop  cultures  were  made  from  leaves  collected 
on  September  28,  1906,  at  Orlando,  and  kept  in  the  laboratory  203  days. 
No  germination  had  occurred  by  April  29,  1907,  when  the  slides  were  dis- 
carded. 

A    SUPER-PARASITIC   OF   ASCHERSONIA    FLAYO-ClTRINA. 

A  super-parasite  belonging  to  the  genus  Cladosporium  has  been  noticed 
as  of  common  occurrence  on  Aschcrsonia  flaio-citrina.  Attention  was  first 
called  to  it  by  A.  W.  Morrill,  who  afterwards  observed  it  at  Orlando  over- 
running this  Aschersonia,  in  the  summer  of  1906.  Later  on  a  brief  report 
was  given  by  E.  W.  Berger.  Plate  VII,  Fig.  4.3,  shows  a  leaf  from  Or- 
lando with  pustules  of  Aschcrsonia  flavo-citrina  covered  over  with  the 
dark  brown  Cladosporium.  This  same  fungus  has  also  been  observed  by 
the  writer  associated  with  sooty  mold  (Meliola)  in  secretions  of  honeydew 
from  Alcyrodes  citri,  and  it  appears  to  aid  at  times  in  smothering  the  white- 
fly  larvae,  as  does  also  the  Meliola.  Cultures  of  this  fungus  were  readily 
obtained  in  5  per  cent,  glucose  agar,  and  the  fungus  was  transferred  to 
potato  plugs.  The  growth  was  rapid  and  the  color  was  the  same  as  on 
the  leaves. 

DISTRIBUTION     OF    ASCHKRSONIA    Kr.AYO-ClTRINA    IN    FLORIDA    IN    1908'. 

Altamonte  Springs, 

Gainesville    (introduced) , 

Largo    (introduced), 

Maithmd, 

New  Smyrna   (introduced), 

( )rlando, 

Oviedo, 

St.   Petersburg    (introduced), 

Winter  Park. 

IV.   YERTICILLIUM  HETEROCLADUM  PENZ. 

The  attention  of  the  writer  was  first  called  to  this  fungus  in  November, 
1!)()5,  b\  E.  H.  Sellards,  Entomologist  of  the  Florida  Experiment  Station, 
who  brought  in  specimens  of  Brown  fungus  from  Palmetto,  Florida,  with 
which  was  associated  a  cinnamon-colored  fungus.  At  the  time  of  its  dis- 


FUXC.I    I'.'KASITIC  UPON  ALEYRODES  CITRI. 

coveiv  on  .-llcyrodcs  citri,  it  was  thought  that  this  fungus  might  possibly 
be  the  spore-bearing  stage  of  the  sterile  "Brown  fungus"  described  by 
Webber,  because  of  its  close  association  with  the  stroma  of  the  Brown 
fungus,  and  since  it  also  resembled  the  Brown  fungus  somewhat  in  color. 
Cultures  of  the  I'crticUlium  hctcrochuium,  however,  together  with  inocula- 
tions oi  larvae  of  Aleyrodcs  citri  in  the  greenhouse,  showed  that  this  fungus 
was  distinct  from  the  Brown  fungus  found  by  Webber  in  1890.  Further 
evidence  of  its  distinct  character  was  subsequently  obtained  when  it  was 
found  in  other  localities  on  Aleyrodcs  citri  and  on  other  insects,  in  no  way 
associated  with  the  Brown  fungus.  At  Palmetto,  where  it  was  first  dis- 
covered, it  was  seen  to  be  attacking  the  long  scale,  Mytilaspis  citric  ola,  that 
occurred  on  the  same  leaves  with  larvae  of  Aleyrodcs  citri.  In  1907  it  was 
found  on  Mytilaspis  glorcrii  at  Gainesville,  quite  independent  of  the  Brown 
fungus.  During  the  same  year,  it  was  found  on  a  species  of  Diaspis  on  the 
leaves  of  Euonymus  Amcricanns  in  the  woods  near  Gainesville.  Later  on 
it  was  observed  unaccompanied  by  Brown  fungus  on  Aleyrodcs  citri  at  St. 
Petersburg,  Fla.  It  was  introduced  by  the  writer  on  larvae  of  Aleyrodes 
citri  on  a  privet  hedge  at  Gainesville  in  the  fall  of  1907.  It  was  also  intro- 
duced by  Mr.  Gaitskill  along  with  the  Brown  fungus  on  larvae  of  Alevrodes 
citri  at  Mclntosh,  during  the  summer  of  1907.  Specimens  of  the  same 
fungus  on  Aleyrodes  citri  were  sent  in  from  Apopka  and  Citra,  Florida, 
early  in  1908.  In  a  few  cases  only  has  it  been  found  in  large  quantities, 
and  as  yet  its  efficiency  as  a  parasite  of  Aleyrodes  citri  is  not  fully  de- 
termined. In  its  parasitism  it  differs  from  the  three  fungi  previously  de- 
scribed, by  attacking  other  insects  not  belonging  to  the  genus  Aleyrodes. 
Several  other  species  of  the  genus  Verticillium  have  been  reported  as 
occurring  on  insects.  1'crlicilliiim  aphidis  Bauml.28  on  plant  lice,  and  Verti- 
cillium minutissimum  Corda29  on  larvae  of  a  small  insect,  were  described 
from  Europe.  An  undetermined  species  of  Verticillium  is  reported  by  J. 
Parkin30  on  a  scale  insect  Asterolccanium  miliaris  which  was  infesting  the 
leaves  of  a  bamboo  bush  in  Ceylon.  Parkin  also  refers  to  Gueguen  as 
authority  for  the  statement  that  1'crticiUium  hctcrochuium  had  been  found 
in  Africa  and  the  Antilles.  It  would  therefore  appear  to  be  a  widely 
distributed  species. 

DESCRIPTION. 

This  fungus  was  first  described  and  figured  by  O.  Penzig/51  in  1882, 
occurring  on  Lecanium  hcsperidum  on  lemon  leaves  in  Italy.  His  descrip- 
tion is  as  follows: 

/'••/•/ /V/7/iMwi    hctcrocladum    Penzig    (Fung.  Agrumic.   N.   108,   Fig.   1193).     Hyphis 

*  Saccardo,  P.  A.    Sylloge  Fungorum,  X,  p.  546,  1892. 

9  Ibid.    IV.  p.  152,  1886. 

'•"Annuls  Roy.  Bot.  Card.,  Peradeniya,  Vol.  Ill,  Part  T,  p.  •}."•,  1906. 

<ii   I'.otanici  sugle  Agrumi  c  sullc  Planti  Aflini,  p.  398,  Tavola  XU    Fig    3    Roma 
1887. 


VERTICIUJUM  HF/TEROCLADUM. 


23 


repentibus,  elongatis,  paulltim  ramosis,  continuis;  ramis  fertilibus  adscendentibus, 
ramnlosis ;  ramulis  ternis  vel  quaternis,  oppositis  vel  alternis,  patentibus,  rectis,  apice 
attenuatis ;  conidiis  in  ramulorum  apice  solitariis,  geminatis  vel  ternis,  saepius  pedi- 
cellis  brevissimis  stiff ultis,  oblongis,  hyalinis,  5.5-6  micr.  long.,  2-3  micrTcfassis. 

Verticillium  heterocladum,  in  general 
appearance,  resembles  the  Brown  fungus 
of  Webber  (Plate  IV,  Fig.  31).  On  close 
examination,  however,  it  is  found  to  be 
strikingly  different.  The  pustules,  which 
are  cinnamon  colored,  are  powdery  on 
the  surface.  Under  the  hand  lens,  they  ap- 
pear brushlike  in  form,  bristling  with 
hyphae.  From  the  edge  of  the  pustules 
there  grows  out  a  creeping  layer  of  white, 
delicate,  interwoven  hyphae.  From  these 
colorless  hyphae,  as  well  as  from  the  top 
of  the  pustules,  there  arise  upright  con- 
idiophores.  These  may  have  eithet  a 
simple  series  of  whorls,  2  to  4  branches 
in  each,  or  the  branches  of  the  whorls 
may  again  be  whorled.  The  conidia  are 
borne  on  the  ends  of  the  ultimate 
branches  (Fig.  10). 

The  conidiophores  are  quite  delicate, 
slender,  hyaline,  150  to  240  microns  by 
times  septate.  The  conidia  are  oblong,  hyaline, 
The  main  body  of  the  cinnamon- 
in 


Fig.  10.  Verticillium  hetei-ocladum.  («)  Conidio- 
phore  with  conidia  forming,  X  450.  (b) 
Conidiophorewith  mature  conidia.  X  450. 
(c)  Conidia,  X  1000. 


o  to  4  microns,  several 
4  to  6  microns  long  by  1.5  to  2.5  thick, 
colored  stroma  when  mature  becomes  powdery 
appearance,  and  under  the  microscope  it  is  found 
that  the  hyphae  have  broken  up  into  short  pieces 
irregular  in  shape  and  length  with  rounded  ends, 
some  of  them  quite  closely  imitating  spores  (Fig. 
11).  These  have  thicker  walls  than  the  conidia, 
and  probably  act  as  reproductive  bodies  in  carry- 
ing the  fungus  through  a  period  of  dry  weather. 


Fig.  11.  Short  hyphal  bodies 
into  which  the  central  por- 
tion of  a  mature  pustule 
breaks  up,  X  450. 


CULTURES. 

Pure  cultures  of  this  fungus  were  made  in  November,  1905,  soon  after 
the  fungus  was  discovered  on  Aleyrodes  citri.  The  next  year  other  cultures 
were  made  and  spores  of  the  fungus  transferred  from  cultures  to  larvae 
of  Aleyrodes  citri  in  the  greenhouse.  The  fungus  was  readily  grown  in  5 
per  cent,  glucose  agar  by  drawing  a  moistened  platinum  needle  over  the 
top  of  the  upright  conidiophores  and  then  washing  it  off  into  the  melted 
agar. 

On  November  12,  1906,  two  petri  dishes  (A  and  B)  of  5  per  cent,  glu- 


21  l-r.\(,i    I'AKASITIC   UPON   ALEYRODES   CITRI. 

cose  agar  were  poured.  A  moistened  needle  was  drawn  over  the  upright 
brush  of  conidiophores  and  washed  into  a  little  bouillon  in  a  test-tube.  In- 
oculations were  made  from  this  with  a  platinum  loop,  nine  loops  being 
transferred  to  A,  and  nine  from  A  to  B. 

On  November  20  (8  days),  120  pure  white  mycelia  appeared  in  A  and  4 
in  1>.  :>  to  4  mm.  in  diameter,  with  reddish  brown  center  and  a  brush  of  up- 
ward growing  white  conidiophores.  On  December  5  (23  days),  the  mycelia 
in  B  were  25  mm.  in  diameter  and  reddish  brown.  On  December  12  (32 
days),  the  mycelia  in  B  were  30  to  35  mm.,  and  cinnamon-colored  almost 
to  the  edges.  By  this  time  a  pustule  was  formed  composed  of  closely  inter- 
woven hyphae  and  closely  resembling  the  pustules  upon  larvae  of  Ale\rodes 
citri  (Plate  V,  Fig.  34)." 

The  fungus  was  transferred  to  test-tubes  of  sterilized  Irish  potato, 
sweet  potato,  rice,  white  cornmeal,  stems  of  canna  and  of  caladium,  and 
bread ;  on  all  of  which  the  fungus  grew  to  some  extent.  It  grew  best,  how- 
ever, on  sweet  potato  and  bread,  over  the  entire  surface  of  which  it  formed 
a  felted  cinnamon-colored  stroma  (Plate  V,  Figs,  32,  33).  On  rice  the 
color  was  that  of  ocher,  and  on  caladium  stems  it  was  brick-red.  On  the 
other  media  the  color  was  nearly  that  of  the  growth  on  5  per  cent,  glucose 
agar. 

The  growth  on  sweet  potato  plugs  was  recorded  as  follows :  On  Novem- 
ber 22.  1  !><•<;,  conidia  from  cultures  made  November  12,  were  rubbed  on  the 
surface  of  the  potato.  On  December  5  (13  days),  a  brown  colored  growth 
had  formed  over  the  surface  of  potato.  By  December  12  (20  days),  the 
entire  surface  was  yellowish  brown.  On  January  15,  1907  (39  days),  the 
entire  surface  was  covered  over  with  a  thick  cinnamon-colored  mat  of 
fungus. 

(.KR MI. NATION    OF    CONIDIA. 

Conidia  were  placed  in  distilled  water  in  hanging  drops.  It  was  found 
that  they  germinated  much  more  rapidly  than  did  the  conidia  of  Ascher- 
sonia.  In  distilled  water,  in  24  hours,  conidia  had  just  begun  to  elongate; 
in  18  hours  a  few  spores  were  found  with  short  hyphal  tubes.  In  bouillon, 
in  24  hours  a  slight  germination  took  place,  the  hyphal  tubes  becoming  as 
long  as  the  spore:  in  :>  days,  the  hyphae  were  120  to  200  microns  long  and 
1  to  \l/2  microns  wide,  and  branched  once  or  twice. 

In  ~>  per  cent,  glucose,  in  24  hours,  the  tube  had  extended  one  to  two 
times  the  length  of  the  spore,  and  in  three  days,  the  growth  had  proceeded 
farther  than  those  in  distilled  water. 

When  germinating,  the  spores  first  swelled,  elongated,  and  then  sent  out 
a  hyphal  tube  from  one  or  both  ends. 

IM  IATION    OF    LARVAE   OF   ALEYRODES    CITRI. 

(  )n  December  (\,  llinii.  small  badly  infested  orange  trees  which  had  pre- 
viously been  in  the  greenhouse,  were  covered  wiih  large  belljars.  Conidia 
from  a  petri  dish  culture  poured  Xovember  12,  I'.MM;  \->\  days  old),  were 
shaken  up  in  sterile  water,  and  this  was  spraved  on  to  the  plants  with  a 
small  atomizer.  In  :>:>  days  several  leaves  were  found  with  stromata  in  a 
spore-bearing  condition,  identical  with  those  from  which  the  culture  had 
originally  been  obtained.  These  had  evidently  developed  sooner  than  35 
•  lays,  and  had  been  overlooked.  Thev  became  powdery  in  appearance  and 
in  all  particulars  were  like  the  natural  pustules. 


SPHAEROSTILBE  COCCOPHIIA. 

On  September  19,  1907,  leaves  containing  VerticiUiuni  hctcrocladum 
were  tied  to  a  twig  of  privet  (Lignstrnm  ovalifolium)  bearing  abundant 
larvae  of  Alc\rodcs  citri.  The  weather  was  moist  for  two  weeks^  after. 

On  October  5  (16  days),  pustules  were  very  evident  on  inany  larvae 
on  leaves  adjacent  to  those  tied  in.  Under  the  microscope  a  mycelium  was 
to  be  seen  inside  the  larvae.  On  October  25  (36  days),  the  fungus  with 
conidia  was  well  established  on  a  few  neighboring  leaves,  but  was  not 
spreading  rapidly  (Plate  V,  Fig.  35). 

On  November  16,  leaves  of  Enonymns  Ainericanus  bearing  a  species 
of  Diaspis  attacked  by  Verticillium  hctcrocladum  were  pinned  on  to  an 
orange  tree  at  Gainesville  by  E.  W.  Berger.  On  December  31,  1907,  three 
pustules  of  freshly  grown  Verticillium  were  found  (one  on  a  scale  insect, 
probably  Lecanium,  and  the  others  apparently  on  larvae  of  Aleyrodcs  citri),. 
on  a  tree  next  to  the  one  in  which  the  fungus  had  been  pinned. 

INSECTS   PARASITIZED,    WITH    LOCALITIES. 

Aleyrodcs  citri:  Palmetto,  Manatee,  St.  Petersburg,  Gainesville,  Apopka, 
Citra,  Mclntosh. 

Mytilaspis  ghverii :    Gainesville. 

Diaspis  sp.  on  leaves  of  Buonyimis  Ainericanus  \    Gainesville. 

Lecanium  sp.  on  orange  leaves:    Gainesville. 

Lecanium  hcspcridnm  on  lemon  leaves:    Italy. 

Mytilaspis  citricola:    Palmetto,  Citra. 

In  Africa  and  the  Antilles  the  host  insect  is  not  known. 

V.    SPHAEROSTILRE  COCCOPHILA  TUL. 

This  fungus,  which  has  a  world-wide  distribution,  and  has  been  re- 
ported as  a  parasite  on  no  less  than  fifteen  different  species  of  scale  insects, 
has  been  found  in  a  few  instances  attacking  larvae  of  Aleyrodcs  citri. 

The  conidial  stage  of  this  fungus   (Figs.  14 
and    15)    was    discovered   by    Desmazieres:}2    on        § 


scales  of  a  coccid  on  young  willow-stems  in 
France,  as  early  as  1848.  It  was  described  un- 
der the  name  Microccra  coccophiia.  The  per- 
ithecia  (Figs.  12  and  13)  were  discovered  by 


Tulasne33  and  described  by  him  in  1865  as  oc- 
curring on   scale  insects   on   species  of  Laurus, 


Salix  and  Fraxinus  in  France,  Italy  and  Amer-  AFig:fly> 


A  „ 


X75.1D!  ica-     Desmazieres'  description  is  as  follows:         Ci^ritxh2eoo 

Microccra,    Desmaz.      Velum    externum    persistens,    membranaceo-floccostim,    dein 

supra    in    lacinias    plures    rumpens  ;    receptaculum    clavatum    carnosttm    e    fibris    sub- 

simplicibus  sporidiiferis   formatum  ;    sporidia   fusiformia,   acuata. 

Microcera    coccophiia    Desmaz.      M.    minutissima,    subcaespitosa    cornuto-conica, 

simplex,  lateritio-rosea,  basi  membrana  tenuissima  albida  vaginato-connata.     Sporidiis- 

paucis,  hyalinis,  elongatis,  utrinque  acutis.     Hab.  in  coccis.     Hieme. 

"  Desmazieres.    Ann.  des  Sc.  Nat.,  Tome  X,  p.  359,  1848. 
Tulasne.    Carpologia,  Vol.   Ill,  105,   1865. 


26  FUNC.I    PARASITIC  UPON  ALEYRODES  CITRI. 

The  ascus  stage  is  described  in  Saccardo's  Sylloge  Fungorum34  thus : 
Sphacrostilbc  coccophila  Tul.  Carp.  III.,  105.— Peritheciis  permultis  supra  et  prope 
stromata  conidiophora  nascentibus,  minimis  globosis,  obtusis,  brevissime  papillatis, 
glaberrimis,  nitide  rubris,  saepe  4-5  sociatis,  senio  collabentibus;  ascis  linearibus, 
60-80X6J/2;  sporidiis  oblique  monostichis,  ovatis,  10X5,  1-septatis,  subhyalinis,  leniter 
constrictis. — Stat.  conid.  Microccra  coccophila  Desm.  Stromate  e  crusta  coccornm 
solitarie  oriundo,  crasse  teretiusculo,  obtuso.  rnbro  2  mill,  alt.;  conidiis  lineari- 
lanceolatis  4-6  locularibus,  65X6  subhyalinis. 

In  1892,  Ellis  and  Everhart-'55  in  "Xorth  American  Pyrenomycetes"  gave 
nearly  the  same  description  in  English,  and  reported  this  fungus  on  a  speci- 
men of  Alnus  scrrulata  collected  in  Pennsylvania,  adding: 

The  conidial  stage  (Microccra  coccophila  Dcsm.)  which  has  been  sent  from 
Florida  by  Dr.  Martin  and  collected  in  Carolina  by  Ravenel  (F.  Am.  286),  has  stroma 
arising  from  various  species  of  dead  bark-lice.  It  is  red,  obtuse  and  about  2  mm. 
high.  The  conidia  are  linear  lanceolate,  5-7  septate  and  56-65X5-6  microns,  nearly 
hyaline. 

D.  McAlpine36  in  describing  the  con- 
/ft'''Vf\  idial   stage   of   this    species   in   Australia 

/i  la  1ft  gives    the   measurements    of   the    conidia 

as  75—103X5^—8^  microns.  Meas- 
urements made  of  a  number  of  Florida 
specimens  from  different  localities  gave 

Fig.  15.   Conidia. 

70—112X3.5—6  microns.  Measurements  x  200. 
of  the  perfect  stage  from  Florida  specimens  were  as 
follows: — Perithecia  350  —  390  long  by  300  microns 
thick.  Divisions  of  perithecial  wall  6 — 10  microns. 
Asci,  70—98X8—12  microns.  Spores  12—18X7—9 
microns. 


HISTORY. 

!•'!•_'.  11.   >i>orodochinm,  or 

°*2K2S2±S^°f  This  fungus  has  been  found  in  nearly  every  coun- 
try in  the  world.  In  1892,  M.  C.  Cooke37  spoke  of  it 
as  common  in  Europe  and  as  a  well-known  parasite  on  dead  Coccus.  In 
the  same  year  it  was  reported  from  Jamaica  by  T.  D.  A.  Cockerell.38  In 
1894,  Henry  Tryon39  reported  it  on  the  long  scale,  the  red  scale  and  the 
circular  black  scale  in  Queensland,  Australia.  In  1897,  it  was  reported 
by  P.  H.  Rolfs40  as  a  parasite  of  the  San  Jose  Scale,  Aspidiotns  pcrniciosus 
Comst  In  1899,  it  was  reported  by  I).  McAlpine41  on  Aspidiotns  anrantii 


**Saccardo.   Sylloge  Fungorum,  II.  p.  :.!.;.  1S83. 

Ellis,  J.  B.  and  Everhart,   .M.    I'..    North  Aim-rioau   Pyrenomycetes,  p.  111.    ]s«i:.'. 
"Fungus  diseases  of  Citric  Tn-rs  in  Australia.  Drpt.  of  Agr.,  Victoria,  p.  113,  1899. 
"Vegetable  Wasps  and  Plant  Worm-,  p.   :;:J:j.   I.i>r.<l<m,    1S92. 
"*Bul.  Botanical  Dept.  of  Jamaica,  No.  :;•'..  p.  r»,   i 
"Queensland  Dept.  of  Agr.,  Hul.    l.  p.   i.v 
"A  Disease  of  San  Jose  Scale,  Fla.  Exp.  Sta.  Bui.  41. 

41  Fungus  Diseases  of  Citrus  Tn-i-s  in  Australia.  Drpt.  of  Agr.,  Queensland,  np    27  and 
28,  1899. 


SPHAEROSTILBE    COCCOPHILA.  27 

Mask,  in  Australia.  In  1900,  P.  H.  Rolfs42  reported  that  Mytilaspis  citri- 
cola  Pack.,  Mytilaspis  gloverii  Pack.,  and  Parlatoria  pergandii  Comst.  were 
all  attacked  by  this  fungus  in  Florida.  The  same  year  F.  B.~  iBafle43  found 
it  common  on  Aspidiotus  ob scums  Comst.  on  water  oaks  in  Alabama.  It 
also  occurs  naturally  in  Georgia,  and  has  been  found  as  far  north  as  Phila- 
delphia, Pa.  In  1901,  Fuller44  reported  finding  the  same  fungus  in  Natal, 
South  Africa.  In  1903,  H.  A.  Gossard45  first  reported  its  occurrence  on  Al- 
eyrodes  citri.  In  1903,  F.  S.  Earle46  found  it  in  Porto  Rico,  and  in  190447 
in  Cuba ;  in  both  places  on  Mytilaspis  citricola.  In  1904,  S.  I.  Kuwana48 
reported  the  fungus  as  present  upon  Aspidiotus  peruiciosus  Comst.  and  on 
Diaspis  pcntagona  Targ.  in  Japan.  He  spoke  of  finding  it  on  the  last- 
named  insect  in  the  mountain  districts.  In  1906,  it  was  reported  by  J. 
Parkin49  as  occurring  upon  Mytilaspis  citricola  Pack,  and  Aspidiotus  aur- 
autii  Mask,  in  Ceylon.  In  1908,  it  was  reported  by  C.  W.  Howard50  from 
the  Transvaal.  It  has  also  been  found  by  E.  W.  Berger  on  Aspidiotus 
hcdcrac  (Vail)  and  Aspidiotus  ancylus  Putnam,  in  Florida. 

Both  the  conidial  and  ascus  stage  of  this  fungus  (Plate  VI,  Figs.  36, 
37,  38)  are  found  commonly  in  Florida,  although  the  latter  is  not  at  all 
common  in  other  parts  of  the  world.  In  Ceylon,  the  perithecia  have  not 
been  found  by  Parkin ;  and  one  would  infer,  from  the  name  Microcera, 
which  is  used  by  D.  McAlpine,  that  the  perfect  stage  is  not  common  in 
Australia. 

RELATION  OF  S.  COCCOPHILA  TO  THE}  SAN  JOSE  AND  OTHER  SCAI^E  INSECTS. 

The  use  of  this  fungus  as  a  practical  remedy  in  combating  the  San  Jose 
scale  was  first  brought  out  by  P.  H.  Rolfs  in  1897,  in  Bulletin  41  of  the 
Florida  Experiment  Station.  This  fungus  was  discovered  by  him  upon  the 
San  Jose  scale  in  northern  Florida  during  the  previous  year.  By  means  of 
pure  cultures  and  infection  experiments,  Rolfs  demonstrated  that  the  San 
Jose  scale  could  be  readily  infected  with  spores  of  this  fungus  grown  upon 
sterilized  bread  or  other  media.  The  results  of  these  experiments  are  given 
in  the  bulletin  referred  to. 

This  fungus  was  also  discovered  to  be  a  common  parasite  of  the  obscure 
scale,  Aspidiotus  obscurus  Comst.,  on  the  twigs  of  water  oaks  (Quercus 
aquatica).  A  simple  method  of  infection  has  been  developed  in  Florida  by 
one  of  the  peach-growers,  Mr.  F.  P.  Henderson,  by  tying  into  the  top  of 


42  Proc.  Fla.  Sta.  Hort.  Soc..  p.  63,  1900. 

43  Ala.  Exp.  Sta.  Bui.  106,  p.  198,  1900. 

4"  First  Rept.  of  Govt.  Entomologist,  Dept.  of  Agr.,  Natal,  p.  99,  1901. 

43  Fla.  Exp.  Sta.  Bui.  67,  p.  623,  1903. 

*  Annual  Rept.  Office  of  Exp.  Sta.,  Washington,  D.  C.,  p.  457,  1903. 

4T  Primer    Informe    Annual    de    la    Estacion    Central    Agronomica    de    Cuba    (1904-05), 

p.    162,   1906. 

48  Japan  Imperial  Agr.  Exp.  Sta.  Rept.,  p.  26,  1904. 
10  Annals  Roy.   Bot.  Card.,   Peradeniya.  Vol.  Ill,   Part  I,  p.  50. 
50  Dept.  of  Agr.,  Transvaal,  Agr.  Journal,  p.  6,  1908. 


l-T.M.I    PARASITIC    l'P().\    A  I.K  YK<  >I>KS   CITRI. 

an  'nfested  tree  a  short  piece  of  .wood  whose  bark  bears  a  good  supply  of 
the  fungus.  This  has  proved  to  be  a  very  effective  way  of  distributing  this 
fungus,  and  has  already  saved  thousands  of  dollars  to  the  peach  and  orange 
growers  of  the  State.  In  addition  to  attacking  Aspidiotns  perniciosus  and 
.  Ispidiotus  ohscurus,  this  fungus  is  effective  in  checking  a  number  of  other 
scale  insects  in  Florida.  It  is,  under  favorable  moisture  conditions,  an 
effectual  parasite  of  Mytilaspis  citricola,  Mytilaspis  gloi'erii,  Aspidiotus 
ficus,  .Ispidiotirs  hciicrac  and  Parlatoria  pergandii.  There  are  times,  in  dry 
weather,  when  these  scale  insects  get  ahead  of  the  fungus ;  but  a  moist 
period  of  a  few  days  will  quite  often  enable  the  fungus  ro  kill  them  off 
almost  completely.  (Plate  VI,  Figs.  3(5,  37  and  38.) 

The  effective  work  of  this  fungus,  and  two  others,  Ophionectria  coc- 
cicola  E.  &  E..  and  Myriangwm  dttriaei  Mont,  upon  the  orange  scales,  is 
readily  shown  by  spraying  an  orange  tree  very  thoroughly  with  Bordeaux 
mixture.  During  the  summer  and  fall  of  1907,  the  author  sprayed  a  num- 
ber of  orange  trees  with  Bordeaux  mixture  for  another  purpose.  The  trees 
were  sprayed  very  thoroughly,  once  in  May,  once  in  July,  and  once  in 
September.  Before  the  first  spraying,  the  trees  were  practically  unhurt  by 
Mytihispis  citricola,  only  a  few  individuals  of  this  scale  being  found  on  any 
part  of  the  trees.  After  the  first  spraying  this  scale  insect  began  to  spread, 
and  increased  slowly  in  numbers  until  November,  when  the  trees  were  badly 
attacked  by  the  scale.  Other  trees  near  by,  that  had  received  no  spray,  were 
as  free  from  scale  as  at  the  first.  The  fungicide  had  evidently  destroyed, 
on  the  sprayed  trees,  the  fungi  that  had  been  all  along  working  upon  the 
unspraved  trees. 

Soon  after  the  discover}-  of  this  fungus  in  Florida  by  P.  H.  Rolfs,  ex- 
periments were  made  by  S.  A.  Forbes51  of  the  Illinois  Experiment  Station, 
Ii.  Smith-"1-  of  the  Xe\v  Jersey  Experiment  Station,  J.  Craig5-'5  of  the 
Canadian  Experiment  Station,  and  F.  A  I.  Webster"'1  of  the  Ohio  Experi- 
ment Station,  to  introduce  Sphacrostilbc  coccophila  on  San  Jose  scale  in 
the  Xorth.  hut  the  climate  of  these  States  did  not  prove  to  be  conducive 
to  its  spread,  and  the  work  was  abandoned. 

I'll  II, A    AS   A    PA  HAS  IT  K   o|-    AI.I-VK  )1)|-S   CITKI. 

As  was  stated  previously.  Spluicrostilhc  coccophila  seems  to  have  been 
first  reported  as  parasitic  on  .llcyrodcs  citri  in  1!M)3  by  H.  A.  Gossard.  It 
was  f<»und  on  larvae  of  .llcymdcs  citri  on  orange  leaves  received  from  Or- 
lando. In  1!Hi:,.  K.  II.  Sellanls"1"1  al.so  reported  having  received  it  from 


"  111.   Kxp.   Sta.   I'.ul.  :,('..  pp.  270  280 

J.   Kxp    St.-..  Kept,   is.  ,,p.    IT.,  179,   1897.     Kept.   P.I.  pp.    145-446.   l.s'.is.     Rept    24    n 

"Canada    Kxp.    I-V.nn    Ki-pt..  p.    11'.'.    Lfi 
1  (  )iii..   Kxp.  Sta.   I'.ul.   in:;,  p.   p.is.   [898, 
"  Kla.  Kxp.   Sta.   Rt-pt  .  p.  87,    L905. 


MI  GROCER A. 


29 


Orlando.     In   1906,  E.  W.   Berger  found   it  on  a  few   whitefly  larvae   at 
Leesburg,  Florida. 

The  effect  of  this  parasite  upon  Aleyrodes  citri  seems-to—be  of  little 
practical  value.  It  has  only  rarely  been  observed  attacking  this  insect,  and 
then  does  not  occur  in  quantity,  as  do  the  other  fungi  before  spoken  of.  It 
is  not  uncommon  to  find  a  large  amount  of  this  fungus  upon  Mytilaspis 
citricola  in  trees  that  are  at  the  same  time  infested  with  larvae  of  Aleyrodes 
citri  on  which  no  fungus  can  be  found. 

LIST    OF    INSECTS    PARASITIZED. 

A  list  of  insects  reported  to  be  attacked  by  this  fungus  is  here  given, 
together  with  the  authority  for  the  report  and  the  localities  in  which  they 
were  found  parasitized : 


NAME  OE  INSECT. 

LOCALITY. 

AUTHORITY. 

Alcvrodcs  citri  R    &  H   !  

Florida    

H    A    Gossard 

Aspidiotus  cinc\lus  Putnam 

Florida 

E   W    Berger 

Aspidiotus  articulatus  Morgan    

Jamaica     .... 

T    D    A.   Cockerell. 

Aspidiotus  articulatus  Morgan    .           

West  Africa 

J    Parkin 

Aspidiotus  articulatus  Morgan    

West  Indies  

J    Parkin. 

Aspidiotus  aurantii  Mask   

Australia    ... 

D    McAlpine 

Aspidiotus  aurantii  Mask           

Natal 

Fuller 

Aspidiotus  aurantii  Mask   

Ceylon  

J    Parkin 

(Chfysompfutlus)    aurantii   Mask 

Transvaal 

C    W    Howard 

Aspidiotus  ficus  Comst 

Florida 

(Cl:i'\soniphalus   cioniduin)    Linn        

Transvaal 

C    W    Howard. 

Aspidiotus  licdcrac    (Vail)        

Florida 

E    W   Berger 

Aspidiotus  obscurus  Conist  

Florida    

P    H    Rolfs. 

Aspidiotus  pcrniciosus  Conist 

Florida 

P    H    Rolfs 

Aspidiotus  pcrniciosus  Comst  

Taoan  

S    I    Kuwana. 

Chionaspis  citri  Comst       

Cuba 

Cook  and  Home. 

Diaspis  pcnta^ona  Tar°"          ... 

Tapan 

S    I    Kuwana. 

l^ionnia   fiornnac   Tar0" 

Mauritius 

J    Parkin 

Ischnaspis  filifonnis           

West  Indies    .  . 

J    Parkin 

Mytilaspis  citricola  Pack           .         

Cevlon 

J    Parkin 

M\iilaspis  citricola  Pack 

Cuba 

F    S    E'arle 

Mytilaspis  citricola  Pack          

Porto  Rico 

F    S    E'arle 

Mytilaspis  ctti'icola  Pack                           .  . 

Florida 

P    H    Rolfs 

Mytilaspis  sloi'crii  Pack    .  .    .        

Florida    

(L,cpidosophcs}   gloi'crii  Pack 

Transvaal 

C    W    Howard 

Parlatoria   bereandii  Comstock.  . 

Florida    . 

P.  H.  Rolfs. 

VI.    MICROCERA  SP. 

Microccra  sp. :  Mycelium  pure  white;  hyphae  delicate,  septate,  loosely 
branching,  hyaline,  4 — 5  microns  thick ;  conidia  at  first  borne  on  the  ends 
of  the  branches,  one  and  two-celled,  oval  to  oblong,  7 — 12X3  microns; 
conidial  tubercules  various  in  size,  cushion-shaped,  pink,  made  up  of  a 
compact  mass  of  conidia  ;  conidia  lunate,  acute  at  both  ends,  3  to  5  septate, 
mostly  28 — 1-0X3.5 — 5  microns.  A  few  conidia  reach  52  microns.  On 
Alcvrodcs  citri  R.  £  H..  on  citrus  trees  in  Florida,  U.  S.  A. 


30 


PARASITIC   I'l'OX    ALEYRODES  CITRI. 


DISCOVERY. 

In  September,  1907,  Prof.  P.  H.  Rolfs,  when  visiting  the  orange  grove 
of  Mr.  F.  Wills  at  Sutherland,  Florida,  noticed  that  a  great  many  larvae 
of  Aleyrodcs  citri  were  dead  or  dying.  None  of  the  known  parasitic  fungi 
were  to  be  seen,  but  by  the  use  of  the  hand  lens  a  whitish  fringe  could  be 
noticed  growing  from  the  edges  of  the  larvae.  Specimen  leaves  were 
brought  back  to  the  laboratory  on  September  13,  and  on  microscopic  ex- 
amination, the  larvae  upon  these  leaves  were  found  to  be  diseased  by  a 
species  of  Microcera.  Leaves  sent  in  by  Mr.  Wills  on  September  26,  were 
found  to  have  even  more  abundant  fungus,  and  nearly  all  the  larvae  were 
dead.  Orange  leaves  sent  in  from  Manatee  a  few  days  later  were  also 
found  to  bear  larvae  infected  with  the  same  fungus.  This  Microcera  has 
since  been  found  at  Largo,  Bayview,  and  Safety  Harbor  by  the  author,  and 
has  been  brought  in  from  Orlando,  DeLand  and  Leesburg  by  E.  W.  Berger. 
A  preliminary  notice  of  this  fungus  was  published  by 
the  author  in  Press  Bulletin  68  of  the  Florida  Experiment 
Station,  "A  Xew  \Yhitefly  Fungus".  This  fungus  presents 
a  fringe  of  delicate  white  hyphae  growing  outward  from 
/j  the  edges  of  the  larvae  (Plate  VI,  Fig.  41).  These  hyphae 

at  first  bear  one-,  two-,  or  three-celled  conidia,  which  are 
oval  to  fusiform  in  shape  (Fig.  16).  Afterwards  there  are 
formed  on  the  edge  of  the  larvae 
pinkish  spore-masses,  which  are 


Kiir.  I'1.,     llyj-liii  «»f 
Microeera    from 


"f  cltn"  x  m' 


edge  of  larva 
showing  branch- 
ing and  forma- 

no.,  of  one-  and     made  up  of  a  compact  mass  of  lunate 

two-celled  coni-  ,  __».  ,_., 

dia.  x  1000.  spores    (Fig.    17).     These  are  3-   to 

5-septate,  and  -jS  to  i<>  microns  long,  by  :>..">  to  5 
microns  thick,  in  fresh  specimens.  When  the  larvae 
are  placed  in  distilled  water  on  a  microscope  slide, 
the  fungus  spores  are  seen  to  float  apart  and  spread  ^om 

out  in  the  water. 

CULTURES. 

Culture-  i»f  this  Microcera  were  grown  much  more  easily  and  quickly 
than  those  of  any  of  the  previously  described  fungi.  This"  fungus  grew 
rapidly  on  nearly  all  kinds  of  media  which  were  tried. 

On  September  II.  I'.in;,  the  day  after  the  fungus  had 
been  examined  and  recogni/ed  as  a  new  parasite  on  Alc\- 
rodes  citri.  three-  sets  of  petri  dish  cultures  of  three  each, 
A.  U.  and  C,  were  prepared  according  to  the  usual  method 
For  isolation.  The  first  Se1  was  made  by  touching  an  in- 
fected larva  with  a  moist  platinum  needle,  and  washing 
the  needle  off  in  test-tube  A.  I',  received  three  loops  from 
A.  and  T  three  loops  f  n  .in  I'.  In  three  days  on  petri  dish 
A.  two  mycelia  and  a  number  of  bacterial  colonies  were 
evident.  In  nine  days,  the  fungus  had  overrun  almost  tin- 
entire  dish,  in  spite-  of  the  bacteria  present,  and  was  pro- 
ducing an  abundance  of  conidia.  \\  and  C  developed  no  fungus. 


Fijf.    IK.      Cr.Ili.1iK 

I-., 111  i, .-i  tube  '-ul- 

on     broiil.     X     I.Vi. 
<  Cullur.-  hud  <1ri«-«l 


MICROCERA.  31 

The  second  set  was  inoculated  with  spores  from  a  test-tube  in  which 
an  infected  larva  had  been  shaken  up  in  water.  In  both  A  and  B,  a  good 
growth  of  fungus  appeared.  The  fungus  just  showed  after  ~24~Iiours.  In 
A,  in  three  days,  there  were  about  50  mycelia.  In  B,  in  three  days,  the 
mycelia,  three  in  number,  had  become  10  to  12  mm.  in  diameter,  loosely 
tufted,  with  numerous  conidia  on  the  upwardly  projecting,  irregularly 
branching  hyphae.  In  nine  days,  the  growth  had  covered  the  entire  surface 
of  the  medium. 

The  third  set  was  inoculated  from  a  test-tube  containing  a  little  sterile 
water,  in  which  two  infected  larvae  had  been  placed.  Only  the  first  petri 
dish  A  developed  a  growth  of  Microcera,  which  grew  as  described  for  the 
second  set. 

The  fungus  in  all  cases  was  of  a  pure  white  color.  It  grew  in  loose 
tufts,  with  upwardly  growing,  very  delicate  hyphae,  forming  a  loose,  fluffy 
mass,  which  soon  collapsed  when  the  cover  of  the  petri  dish  was  removed. 
A  microscopic  examination  of  this  growth  showed  that  it  was  made  up  of 
irregularly  branching  hyphae  bearing  conidia. 

All  intermediate  shapes  of  spores  from  the  oval  one-celled  conidium, 
to  the  septate  lunate  conidium,  could  be  found  in.  the  same  culture.  (Figs. 
1G,  17,  18).  It  may  be  remarked  in  this  connection,  that  in  the  cultures  of 
Sphaerostilbc  coccophila  made  by  P.  H.  Rolfs  in  1897,  the  conidial  stage 
of  which  has  been  referred  to  Microcera,  these  one-  and  two-celled  conidia 
appeared,  and  are  figured  by  him  in  Bulletin  41  of  the  Florida  Experiment 
Station,  Plate  II.  Judging  from  the  growth  of  Microcera  sp.  in  cultures, 
it  would  probably  fit  into  the  genus  Fusarium,  but  since  the  distinction  be- 
tween Microcera  and  Fusarium  is  rather  vague,  we  prefer  to  hold  to  the 
name  Microcera  until  the  perfect  stage  is  worked  out.  Perithecia  of  this 
fungus  appear  to  be  developing  at  the  present  time  on  culture  media. 

On  September  18,  two  test-tubes  of  standard  agar,  one  of  Irish  potato, 
and  one  of  rice,  were  inoculated  by  drawing  a  moist  needle  over  the  top 
of  culture  P>  of  the  second  set  poured  on  September  14.  On  agar  tubes 
there  seemed  to  be  some  evidence  of  growth  in  three  or  four  hours.  On 
September  21  (3  days),  tufts  of  white  mycelium  were  formed  over  the 
entire  surface.  On  November  20,  the  agar  had  begun  to  shrink  away  from 
the  sides  of  the  tube,  and  the  fungus  had  grown  down  over  the  sides  of 
the  medium.  On  Irish  potato,  September  28,  almost  the  entire  surface  was 
covered  with  a  snowy  white  growth  of  fungus.  On  rice  in  a  50  cc.  flask, 
by  November  11  (54  days)  the  entire  surface  was  covered  with  growth, 
and  the  spaces  between  the  rice  grains  were  packed  with  a  fungus  mycelium. 
The  mycelium  was  very  thick,  matted,  and  pink  on  the  sides  near  the  glass 
(Plate" VI,  Figs.  39  and  40). 

On  September  25,  a  test-tube  and  a  flask  of  rice,  and  two  tubes  of  bread, 
were  inoculated  from  the  same  culture  as  before.  On  rice,  September  28 
(3  days),  a  delicate  growth  10  mm.  high  was  formed  in  the  test-tube.  The 
rice  had  turned  pinkish  from  the  top  to  ^4  inch  down  on  the  sides.  In  the 
flask  almost  the  entire  surface  was  covered,  and  was  pinkish  at  the  base  on 
the  sides  of  the  rice.  By  October  18  (23  days)  the  fungus  had  grown 
through  all  the  available  spaces  in  the  medium,  forming  a  pinkish  matted 


FUNGI    PARASITIC    UPON    AI.KYRODES  CITRI. 

-rnwtli.  (  )n  November  11,  numerous  conidia  were  present  in  pink  masses 
on  tin-  sides  of  the  rice.  (  )n  the  bread,  on  September  28  (5  days),  a  delicate 
white  growth  was  formed  over  the  upper  surface.  On  October  10  (15 
days),  the  growth  had  taken  up  every  available  space  in  the  pores  of  the 
bread.  giving  it  a  pinkish  matted  appearance. 

(  )n  (  October  11  the  following-  cultures  were  made  by  transferring  spores 
from  the  bread  cultures  of  September  25,  which  had  been  transferred  once 
before.  Three  tubes  of  agar,  one  of  sweet  potato,  one  of  Irish  potato,  one 
of  rice  in  a  .">()  cc.  flask,  and  one  of  bread  were  used.  Notes  were  taken  on 
(  >ctoher  1!'  only.  In  the  three  agar  tubes,  which  reacted  1.0,  1.5  and  2.0 
respectively  to  phenolphthalein.  the  growth  was  about  one  inch  high  with 
abundance  of  conidia.  There  was  no  noticeable  difference  in  the  growth. 
(  )n  sweet  potatoes,  a  pure  white,  delicate  growth  appeared ;  on  Irish  po- 
tatoes, a  very  abundant  growth;  on  rice,  an  abundant  growth  with  a -pink- 
ish color  on  the  surface,  and  thick  mycelium  between  the  rice  grains. 

INKKCT10N    OK    AUCYROPKS    CITRI. 

On  September  1!>,  1!M)7,  infection  experiments  were  made  on  healthy 
whiten*}-  larvae  from  cultures  of  this  fungus.  The  larvae  were  on  the  leaves 
of  a  privet  hedge  (Ligustnuii  ovali folium)  in  Gainesville.  The  following 
is  taken  from  notes  made  at  the  time  of  the  experiments : 

Healthy  larvae  were  very  abundant  on  the  privet  leaves.  The  weather 
was  damp  after  a  rain.  Inoculations  were  made  from  3  to  5  p.  M. 

\o.  1.  Inoculation  was  made  from  culture  of  September  14;  conidia 
were  penciled  on  the  under  side  of  the  leaves  on  one  branch  with  a  moist 
camel  s-hair  brush ;  a  piece  of  cheese  cloth  was  tied  around  the  inoculated 
branch.  On  September  21  no  conidia  were  found;  the  cheese  cloth  was 
removed.  On  September  2<S,  no  conidia  were  found.  On  October  5,  abund- 
ant conidia  of  Microcera  were  present.  On  October  25,  about  50  per  cent, 
of  the  larvae  were  dead. 

\o.  'I.  Inoculation  was  made  from  same  culture,  penciled  on  as  in  No. 
1,  but  not  covered  with  cheese  cloth.  On  September  28,  no  spores  were, 
found.  On  October  1,  spores  of  Microcera  were  present.  On  October  5, 
pink  spore-masses  were  developed  on  the  edges  of  larvae.  P>y  October  25, 
about  -V>  per  rent,  of  larvae  were  dead. 

\o.  3.    Conidia  were  penciled  on  as  above,  and  not  covered  with  cheese 

cloth.     On    September  21.   no   spores  were  found.     On   September  28,  no 

spores   were    found.     On   October    1.    Microcera   spores   were  present.   '  On 

•nk  spore  masses  were  present  on  the  edges  of  the  larvae.     (  )n 

(  )cto],er  2~>.  about  ."in  per  cent,  of  the  larvae  were  dead. 

Xo.  I.  Inoculation  was  made  from  larvae  on  citrus  leaves  from  Mana- 
\o  cheese  cloth  was  tied  around.  (  )n  September  21.  larvae  seemed  to 
be  attacked  by  a  small  fungus,  which  looked  like  the  Microcera  of  the 
cultures.  The  conidia  were  one-  and  two-celled.  (  )n  September  2«,  abund- 
ant spores  of  .Microcera  « >n  .lead  larvae  were  found,  and  live  larvae  with 
filaments  ,,f  fnngns  within.  About  (in  per  cent  estimated  dead.  On  Octo- 
ber ").  pink  conidial  masses  were  evident  on  edge's  of  larvae. 

No.  5,  A  branch  as  a  check  was  not  inoculated.  l,nt  tied  up  with  cheese 
cloth.  On  September  21,  no  COnidia  of  Microcera  were  to  be  found.  On 
September  2s.  n«>  conidia  of  .Microcera  to  be  found. 


MICROCERA.  33 

Xo.  6.  A  branch  near  Xo.  5  was  neither  inoculated,  nor  tied  with  cheese 
cloth.  On  September  21,  no  spores  of  Microcera  were  to  be  found.  On 
September  28,  no  spores  of  Microcera  were  found. 

X"o.  7.  A  branch  above  Xo.  4  was  neither  inoculated,  nor  tied  with 
cheese  cloth.  When  examined  on  September  28,  no  Microcera  could  be 
found. 

During  the  first  two  weeks  after  these  infection  experiments  were  made 
there  were  frequent  rains,  and  the  weather  was  quite  moist.  This  was  fol- 
lowed by  two  weeks  of  drier  weather  during  which  the  fungus  apparently 
ceased  to  grow.  These  inoculation  experiments  show  that  under  favorable 
climatic  conditions  like  those  under  which  they  were  carried  on,  the  larvae 
of  Ale yr odes  citri  may  readily  be  infected  either  directly  from  previously 
infected  larvae,  or  from  pure  cultures. 

GERMINATION    OF    CONIDIA. 

The  conidia  of  Microcera  germinated  quite  readily  in  water.  On  Octo- 
ber 3,  a  hanging  drop  culture  was  made  with  conidia  from  a  potato  culture. 
In  24  hours,  one  of  the  cells  of  the  conidia,  usually  the  end  cell,  sent  out 
hyphal  tubes  to  a  distance  of  one  to  four  times  the  length  of  the  conidia. 
On  the  end  of  a  number  of  these  were  seen  small  oval  sporids  (Fig.  19). 
In  48  hours  the  hyphae  were  6  to  7  times  the  length  of  the  conidia,  some 
of  them  branched  as  in  Fig.  19,  and  many  sporids  had  formed.  In  six 
days  the  branching  hyphae  were  j\  ^r-^Z^  ^!k*" ' ' '  '-^^j-^ 

prominent,  with  many  sporids.     The       /V^^"*^J>  ^^v  "*"^^?\ 

segments  of  the  conidia  had  become     if  ^\ 

swollen,    thus    causing    constrictions  G?3  ° 

Fig.  19.    Conidium  of  Microcera  germinating 

at  the   septa.  and  forming  sporids.  (a)  Conidium.  (?>)  hyphal 

tube,  (c)  sporid,  X  450. 

VARIATION    IN    SIZE   OF   CONIDIA. 

The  measurements  of  conidia  at  various  times  and  under  various  con- 
ditions indicated  a  considerable  variation  in  size.  The  greatest  variation 
was  in  the  length.  As  has  been  said,  the  conidia  varied  from  oval  one- 
celled  spores  to  long  lunate  spores.  Measurements  of  lunate  spores  on 
larvae  were  as  follows : 

On  September  23,  the  first  specimen  from  Sutherland  after  drying  bore 
conidia  measuring  28 — 40  by  3.5 — 5  microns.  On  September  26,  the  second 
lot  of  specimens  from  Sutherland,  while  still  fresh,  contained  conidia  meas- 
uring 36 — 45X3.5 — 4.5  microns.  On  October  5,  privet  leaves  from  inocu- 
lation experiment  X^o.  4,  at  Gainesville,  while  still  fresh,  bore  conidia  meas- 
uring 31—52X3.5 — 4.5. 

Measurements  of  lunate  spores  in  cultures  were  as  follows: 

On  September  17,  conidia  from  cultures  made  September  14  measured 
21 — 32X3.5 — 4.5  microns.  On  XTovember  21,  conidia  from  culture  on 
potato,  measured  12  to  30  microns  long;  two-celled  conidia  were  12  microns, 
the  others  longer.  On  February  2,  1908,  from  cultures  101  days  old,  made 
October  26,  1907,  on  white  cornmeal  cultures  not  dried  out;  conidia  in  pink 


34  FUNGI  PARASITIC  UPON  ALEYRODES  CITRI. 

cushion-shaped  masses,  5-septate,  40—60  microns  long;  most  of  them  40 
microns,  few  60  microns.  On  June  2,  1908,  from  culture  on  bread  made 
September  25,  1906,  dried  out;  conidia  15—30X3—4.5  microns. 

DISTRIBUTION    OF    MICROCERA    SP.    IN    FLORIDA. 

Sutherland September  13,    1907. 

Manatee September  18,    1907. 

Gainesville September  21,    1907.   (Introduced.) 

Leesburg October  11,    1907. 

Orlando November  25,   1907. 

Largo November  1907. 

Titusville December  3,  1907. 

Safety  Harbor March,  1908. 

VII.   THE  BROWN  FUNGUS  OF  ALEYRODES  CITRI. 

In  March,  1896,  H.  J.  Webber56  discovered  this  fungus  on  whitefly 
larvae  in  the  grove  of  J.  H.  Viser,  Manatee,  Florida.  During  the  summer 
of  that  year  the  fungus  spread  rapidly  through  the  Viser  grove,  and  was 
observed  to  be  a  very  effective  parasite  of  Aleyrodes  citri.  As  no  fructifica- 
tion of  any  kind  has  been  found  in  connection  with  this  fungus,  it  has  not 
been  classified.  It  has  been  known  since  its  discovery  as  the  "Brown 
Fungus"  of  the  whitefly  (Plate  VII,  Fig.  42). 

INSCRIPTION. 

Webber57  gave  a  general  description  of  this  fungus  in  Bulletin  13  of 
the  Division  of  Vegetable  Physiology  and  Pathology,  as  follows : 

The  mature  stroma  is  compressed  hemispherical,  frequently  having  a  slight  de- 
pression in  the  apex  over  the  center  of  the  insect,  where  the  hyphae  come  together  as 
they  spread  from  the  edges  of  the  scale  in  their  development.  The  size  varies  greatly, 
according  to  the  stage  of  development  of  the  insect  attacked.  In  very  young  larvae 
it  is  from  l/4  to  l/2  a  millimeter  in  diameter.  In  mature  larvae  and  pupae  it  frequently 
reaches  2  millimeters  in  diameter.  The  thickness,  or  height,  also  varies  in  like  manner, 
specimens  on  mature  larvae  or  pupae  being  usually  from  175  to  260  microns,  while 
those  on  young  larvae  are  much  thinner.  *  *  *  The  stroma  is  commonly  seal 
brown,  with  a  shade  of  chestnut,  but  becomes  slightly  darker  with  age.  *  *  *  The 
hyphae,  which  make  up  the  body  of  the  stroma,  are  light  brown,  very  tortuous,  and 
but  slightly  branched.  Those  in  the  body  of  the  insect  are  of  similar  character,  but  a 
much  darker  brown.  From  the  base  of  the  stroma  a  ground  mycelium,  or  hypothallus, 
spreads  out  in  all  directions  on  the  surface  of  the  leaf,  forming  a  compact  membrane 
near  the  stroma,  but  becoming  gradually  dispersed  into  separate  filaments.  *  *  * 
The  hyphae  of  the  hypothallus  are  colorless,  sparingly  branched,  mostly  continuous, 
having  only  an  occasional  septum,  and  are  from  5  to  7  microns  in  diameter.  In  some 
places  in  the  hypothallus.  where  the  hyphae  are  apparently  somewhat  massed  and 
knotted,  tlu-y  become  light  brown,  similar  in  color  to  the  isolated  hyphae  of  the 
stroma. 


Div.  of  Veg.  Phys.  &  Path.,  Washington,   1).  C..   I',ul     \\\    p.  "7     is«»7 
Ibid.     pp.  28-30. 


THE  BROWN   FUNGUS.  35 

BROWN    FUNGUS    OF    PARKIN. 

J.  Parkin58  in  writing  of  the  Ceylon  forms  of  fungi  parasitic  on  Aley- 
rodes,  mentions  having  found  on  three  different  kinds  of  teav^s  a  brown 
sterile  fungus,  which  he  thinks  is  similar  to  the  one  described  by  Webber 
on  Aleyrodes  citri.  He  also  states  that  these  brown  pustules  were  in  many 
cases  closely  associated  with  Aschersonia  aleyrodis  of  Webber,  and  suggests 
the  possibility  of  one  being  a  form  of  the  other.  In  regard  to  this  point  he 
writes : 

Intermingled  with  the  brightly  colored  Aschersonia  stromata  on  the  leaf  of 
Flemingia  strobilifera  were  other  brown  ones.  Many  of  these  latter  were  evidently 
old  or  arrested  Aschersonia  stromata,  as  sections  of  them  revealed  closed  pycnidia. 
Others  again  were  flatter,  more  nearly  resembling  Webber's  brown  fungus,  thus  sug- 
gesting the  possibility  of  all  these  sterile  pustules  being  really  connected  with  Ascher- 
sonia. The  two  fungi  often  appear  in  association  on  the  same  scale  and  even  on  the 
same  leaf.  Webber  mentions  that  A.  aleyrodis  was  present  on  those  orange  bushes 
containing  also  the  "brown  mealy  wing  fungus".  In  the  Ceylon  specimen  on  Meme- 
cylon  the  two  were  intimately  associated.  Atmospheric  conditions  such  as  dryness 
may  also  influence  the  development  of  the  Aschersonia  as  to  induce  it  to  assume  a 
sterile  resting  form.  This,  when  conditions  are  again  favorable,  might  send  out  in- 
fecting hyphae  over  the  leaf  surface.  Webber's  account  of  how  this  brown  fungus 
develops  and  spreads  hardly  favors  such  a  view.  However,  its  close  association  with 
Aschersonia  is  a  point  to  be  kept  in  mind.  By  cultures  perhaps  this  sterile  form  might 
be  induced  to  form  some  fructifications,  and  so  a  clue  to  its  nature  and  relationship 
might  be  obtained. 

The  cultures  of  Aschersonia  aleyrodis  and  Aschersonia  flavo-citrina  made 
by  the  author  on  various  media  and  at  different  times  of  year  with  varying 
amounts  of  water,  never  showed  any  tendency  to  develop  the  brown  sterile 
form  of  the  Brown  fungus.  In  Florida  there  seems  to  be  no  evidence  to 
indicate  any  connection  between  this  sterile  Brown  fungus  and  the  Ascher- 
sonias  parasitic  upon  Aleyrodes  citri. 

METHODS    OF    INTRODUCTION. 

Webber,  in  the  bulletin  previously  referred  to,  describes  in  some  detail 
the  method  of  introducing  this  fungus  into  trees  infested  with  Aleyrodes 
citri  by  pinning  in  leaves,  or  by  planting  young  fungus-bearing  trees  in 
such  a  way  that  their  leaves  would  come  in  contact  with  the  larvae-bearing 
leaves  to  be  infected  with  fungus.  E.  W.  Berger59  has  recently  produced 
some  infection  by  grinding  up  the  brown  stromata,  stirring  with  water,  and 
spraying  this  water  upon  infested  leaves. 

A  number  of  attempts  have  been  made  by  the  writer  to  grow  cultures  of 
this  fungus  in  the  laboratory,  but  so  far  he  has  been  unsuccessful.  In  one 
case  where  stromata  of  the  brown  fungus  were  placed  close  to  a  drop  of 
agar  in  a  hanging  drop  culture,  short  tortuous  hyphae  were  seen  to  grow 


158  Annals  Roy.  Bot.  Card.  Peradeniya,  Vol.  Ill,  Part  I,  p.  52,  1906. 
C9Fla.  Exp.  Sta.  Bui.  88,  p.  64,  1906. 


:;r,  „      i-r.\(,i  PARASITIC  UPON  ALEYRODES  CITRI. 

out  from  the  edge.     This  is  the  only  growth  that  lias  so  far  been  observed 
under  artificial  conditions. 

niSTKII'.r  H<>.\    OF  THE  BROWN   FUNGUS. 

Florida. — Alva.  Bartow,  Buckingham,  Bradentown,  Fort  Myers,  Largo, 
Leesburg,  Manatee,  Oneco,  Orlando,  Palmetto,  St.  Augustine  and  St.. 
Petersburg,  on  Ale yr odes  citri. 

Ceylon,  as  reported  by  J.  Parkin,  on  various  species  of  Aleyrodes. 

SUPPLEMENTARY  NOTES. 

1.  Since  the  above  has  been  written,  what  appear  to  be  the  spores  of 
the  Brown  fungus  of  Aleyrodes  citri  have  been  discovered.  These  spores 
are  germinating  in  hanging  drop  cultures  of  sugar  solutions,  and  are  pro- 
ducing hyphae  that  seem  to  be  identical  with  those  of  the  Brown  fungus. 
Further  studv  is  needed  to  prove  the  relationship  of  these  spores  to  the 
Brown  fungus. 

V.  A  species  of  Sporotrichuin  has  been  discovered  upon  the  adult  and 
larva  of  Aleyrodes  citri.  This  fungus  seems  to  be  responsible,  during  damp 
weather,  for  the  premature  death  of  great  numbers  of  adults.  Cultures  and 
inoculation  experiments  are  being  carried  on,  the  results  of  which  will  be 
published  later. 

3.  Since  the  writing  of  this  thesis  it  has  been  shown  by  Dr.  E.  W.  Berger, 
Entomologist  of  the  Florida  Experiment  Station,  that  the  insects  hitherto 
designated  as  Ale\rodes  citri  comprise  two  distinct  species  of  Aleyrodes; 
one  with  smooth  eggs  and  clear  wings,  and  the  other  with  rough  eggs 
covered  with  a  delicate  net  of  five-  and  six-sided  meshes,  and  wings  with 
a  smoky-colored  area  at  the  end  of  each  fore  wing.  Specific  differences 
have  also  been  observed  in  the  first  and  fourth  stage  larvae.  (See  Press. 
Bulletin  t)T,  Fla.  Agri.  E\p.  Sta.,  and  Proc.  Fla.'Sta.  Ho'rt.  Soc.,  p.  86,  1908.) 
Dr.  Berger's  observations  and  also  those  of  the  writer  seem  to  show  that 
these  two  species  of  Aleyrodes  are  differently  attacked  by  the  Aschersonias 
(A.  oleyrodis  and  .•/.  flavo-citrina},  and  also  by  the  Brown  fungus  and 
Microccra  sp.  Aschersonia  flaz'O-citrina  attacks  readily  onlv  the  smoky- 
winged  Aleyrodes.  but  will  attack  the  clear-winged  species.  Aschersonia 
ulcyrodis  and  the  Brown  fungus  attack  both  species  of  Aleyrodes  in  an  equal 
degree,  but  the  greater  number  of  the  specimens  so  far  observed  have  been 
found  upon  the  clear-winded  species.  The  Microceni  has  been  found  on 
both  species  of  Aleyrodes,  although  it  is  more  effective  upon  the  smoky- 
winged  .species.  The  infection  experiments  described  in  the  foregoing  pages 
with  cultures  of  Microccni  sp.  (page  :;•>)  and  /  V/7/V/7///////  hetcrochuinm 
(pag€  &4)  were  made  up.  .11  the  clear-winged  species.  The  infection  ex- 
periments also  made  by  E.  \Y.  Berger  at  St.  Petersburg  and  ('.ainesville-- 
i  page  1'i)  weft  aNo  upon  the  clear-winged  Aleyrodes. 

October  1,  1908. 


SUMMARY.  37 

SUMMARY. 

1.  Entomogenous  species  of  fungi  representing  many  different  genera 
have  been  described  in  the  past  hundred  or  more  years. 

2.  These  have  not,  until  recent  times,  been  studied  from  an  economic 
standpoint.     The   greatest   success   in   the   use   of   fungi   to   combat   insect 
pests  seems  to  have  been  attained  in  Florida,  where  proper  conditions  of 
temperature  and  moisture  are  present. 

3.  Aleyrodes  citri  R.  &  H.,  known  since  1885  as  a  pest  to  citrus  trees  in 
Florida,  has  spread  to  many  citrus  districts  since  that  time,  doing  much 
damage  chiefly  by  creating  conditions  favorable  to  the  growth  of  Meliola. 

4.  A  study  of  the  fungi  parasitic  upon  Aleyrodes  citri  shows  that  there 
are  at  least  six  species,  five  of  which  have  been  grown  upon  culture  media 
in  the  laboratory. 

5.  Aschersonia  ale\rodis  Webber  is  the  most  widely  distributed  fungus 
parasite  of  Aleyrodes  citri.     It  is  easily  isolated  and  grown  in  pure  cultures 
in  5  to  10  per  cent,  glucose  agar  medium,  maturing  a  stroma  in  30  to  40 
days. 

6.  Healthy  larvae  of  Aleyrodes  citri  may  be  infected  from  cultures  of 
this  fungus  by  spraying  a  mixture  of  conidia  in  water  on  trees  infested  with 
Aleyrodes  citri. 

7.  Aschersonia  flai'o-citrina   P.    Henn.,   which   was   recently   found   in 
eastern  Florida,  is  also  an  important  parasite  of  Aleyrodes  citri.     Its  growth 
on  culture  media  is  the  same  as  that  of  A.  aleyrodis. 

8.  Conidia  of  both  of  the  Aschersonias  germinated  best  in  a  5  to  10  per 
cent,  solution  of  glucose  in  water.     Percentages  of  sugar  above  or  below 
this  retarded  germination.     Conidia  from  stromata  dried  in  the  laboratory 
for  more  than  28  days  failed  to  germinate. 

9.  Verticillinni  heterocladnni   Penz.  has  been  recently  shown  to  occur 
parasitically  upon  Aleyrodes  citri.     It  has  also  been  observed  on  a  number 
of   other    insects.      Cultures   and    inoculation    experiments    show    that   this 
fungus  is  distinct  from  the  "Brown  fungus",  which  it  somewhat  resembles  in 
general  appearance,  and  with  which  it  is  frequently  found  associated. 

10.  The  growth  of  this  fungus  in  cultures  is  much  more  rapid  than  that 
of  the  two  species  of  Aschersonia  described. 

11.  Sphaerostilbe  coccophila,  known  since  1848,  is  world-wide  in  dis- 
tribution, and  has  been  reported  on  no  less  than  fifteen  species  of  scale 
insects,  in  addition  to  being  found  on  Aleyrodes  citri. 

12.  Sphaerostilbe  coccophila  has  been  used  in  Florida  as  an  effective 
parasite  in  controlling  the  San  Jose  scale  and  other  scale  insects.     In  more 
northern  States  it  has  not  proved  to  be  effective.     It  is  possibly  a  weak 
parasite  of  Aleyrodes  citri. 

13.  Microcera  sp.,  recently  discovered,  has  been  found  in  a  number  of 
places  in  Florida  attacking  larvae  of  Aleyrodes  citri.     Abundant  cultures  of 


38  Kr.xr.I    I'ARASITIC   UPON   ALEYRODES   CITRI. 

this  fungus  may  be  grown  in  a  few  days,  and  larvae  of  Aleyrodcs  citri  may 
be  infected  from  these  cultures.  Conidia  of  this  fungus  vary  greatly  in  size 
under  different  conditions  of  growth. 

1  1.  The  Brown  fungus,  known  in  Florida  since  1896,  has  never  been 
observed  to  produce  spores  and  is  therefore  unclassified.  Its  growth  and 
development  on  Aleyrodcs  citri  were  described  by  Webber.  All  attempts  to 
grow  this  fungus  in  pure  cultures  have  failed.  (See,  however,  Supplement- 
ary Note  1.) 

BIBLIOGRAPHY. 

The  literature  referred  to  in  this  bibliography  is  grouped  under  seven  heads,  corre- 
sponding to  the  seven  divisions  under  which  the  subject  is  discussed.  The  references 
in  each  division  are  arranged  in  chronological  order.  All  but  three  of  the  papers 
have  been  seen  by  the  author.  These  three  are  designated  by  an  (*)  asterisk. 

GENERAL,    LITERATURE. 

('88)  Forbes,  S.  A.  On  our  present  knowledge  concerning  Insect  Diseases.  Psyche, 
Vol.  V,  pp.  3-12,  1888-90.  (Bibliography,  pp.  15-22.) 

('88)  Thaxter,  Roland.  The  E'ntomophthoraceae  of  the  United  States.  Memoirs 
of  the  Boston  Soc.  of  Nat.  History,  Vol.  IV,  No.  6,  1888.  (With  bibliography.) 

('88)  Lugger,  Otto.  Fungi  Which  Kill  Insects.  Univ.  of  Minn.  Ann.  Kept.  Agr., 
pp.  380-392,  1888. 

('92)    Cooke,  M.  C.    Vegetable  Wasps  and  Plant  Worms,  London,  1892 

('93)  Riley,  C.  V.  and  Howard,  L-  O.  Insect  Life,  Div.  of  Ento.,  Wash.,  D.  C., 
Vol.  V,  No.  4,  p.  220,  1893. 

('95)  Pettit,  R.  H.  Studies  in  Artificial  Cultures  of  Entomogenous  Fungi.  Cor- 
nell Univ.  Agr.  Exp.  Sta.  Bui.  97,  1895  (with  bibliography). 

('95)  Forbes,  S.  A.  Experiments  With  the  Muscadine  Disease  of  the  Chinch- 
bug,  etc.  111.  Agr.  Exp.  Sta.  Bui.  38,  is-.i:, 

('97)  Rolfs,  P.  H.  A  Disease  of  the  San  Jose  Scale.  Fla.  Agr.  Exp.  Sta  Bui  41 
1897. 

('98)    Forbes,  S.  A.     111.  Agr.  Exp.  Sta.  Bui.  56,  pp.  270-280,  1898. 

('06)  Parkin,  J.  Fungi  Parasitic  Upon  Scale  Insects  (Coccidae  and  Aleyrodidae), 
etc.  Ann.  Roy.  Bot.  Gardens  Peradcniya,  Vol.  Ill,  Part  I.  (With  bibliography.) 

ASCHERSONIA     AI.KVKODIS     \YEHBER. 

('94)  Webber,  H.  J.  Preliminary  Notice  of  a  Fungus  Parasite  on  Aleyrodes 
citri.  Journ.  of  Mycol.,  Vol.  VII,  No.  4,  p.  363,  1894. 

('96)    Webber,  H.  J.     Proc.  Fla.  State  Hort.   Soc.,  p.  73,  1896. 

('96)  Webber,  H.  J.  The  Principal  Diseases  of  Citrus  Fruits  in  Florida.  Div. 
of  Veg.  Phys.  and  Path.,  Bui.  8,  Washington,  D.  C.,  p.  27,  1896. 

('97)  Webber.  H.  J.  Sooty  Mold  of  the  Orange.  Div.  of  Veg.  Phys  and  Path 
Bui.  13,  p.  20,  Washington,  D.  C.,  1897. 

('99)    Saccardo,  P.  A.     Sylloge  Fungorum,  XIV.  p.  991,  1899. 

('00)    Hume,  H.  H.     Some  Citrus  Troubles.     Fla.  Agr.  Exp.  Sta.  Bui.  53,  p.  164, 

('03)    Gossard,  H.  A.     Fla.  Agr.  Exp.  Sta.  Bui.  67,  pp.  622-623,  190.: 

('04)    Hume,  H.  H.     Citrus  Fruits  and  Their  Culture,  pp.  547-550    Jacksonville 

Florida,  1'.»<u. 

('05)    Sellards.  E.  II.     Fla.  Agr.  Exp.  Sta.  Rept.,  pp.  26-27,  1905 

('06)     Earle,  F.  S.     Primer  Informe  Anual  de  la  Estacion  Central  Agronomica  de 

Cuba,  1904-1905,  p.  K.'.>.   L906, 

('06)    Parkin,  J.    Fungi  Parasitic  Upon  ScaK-  Insects.     Annals  of  Royal  Bot   Card 

Peradeniya,  Vol.  Ill,  Part   I.  ,,.  :;r,,   i<>06. 

('06)    Berger,  E.  W.     Fla.  Agr.  Exp.  Sta.  Rept..  p.  xix,  v.MMi. 
('07)     Berger,  E.  W.     Fla.  Agr.  Exp.  Sta.  Bui.  88,  pp.  54-c.:,,   1907 
('07)    Berger,  E.  W.     Fla.  Agr.  Exp.  Sta.  Rept.,  p.  xxxi.   11107 
('07)     Fawcett,  H.  S.     Fla.  Agr.  Exp.  Sta.  Rept.,  p.  xlviii,  1907 


BIBLIOGRAPHY.  39 

('07)  Kirkaldy,  G.  W.  and  Kotinsky,  J.  Board  of  Commissioners  of  Agr.  and 
Forestry,  Div.  of  Entomology,  Hawaiian  Sugar  Planters'  Exp.  Sta.,  Bui.  2,  pp.  57  and 
60,  1907. 

('08)    Berger,  E.  W.     Fla.  Agr.  Exp.  Sta.  Press  Bui.  80,  1908^__  ___ 

('08)  Cook,  M.  T.  and  Home,  W.  T.  Insects  and  Diseases  of  Orange.  Cuba 
Agr.  Exp.  Sta.  Bui.  9,  p.  31,  1908. 

('08)  Rolfs,  P.  H.  and  Fawcett,  H.  S.  Fungus  Diseases  of  Scale  Insects  and 
Winterly.  Fla.  Agr.  Exp.  Sta.  Bui.  94,  1908. 

ASCHERSONIA   FT.AVO-CITR1NA    P.    HENN. 

('02)  Hennings,   P.     Hedwigia,  Vol.  41,  p.  307,  1902. 

('04)  Hennings.     Festschrift  fur  P.  Ascherson,  p.  68,  1904. 

('06)  Saccardo.     Sylloge  Fungorum,  xviii,  p.  413,  1906. 

('07)  Rolfs,  P.  H.     Fla.  Agr.  Exp.  Sta.  Rept.,  p.  16,  1907. 

('07)  Berger,  E.  W.     Fla.  Agr.  Exp.  Sta.  Rept.,  pp.  31,  34  and  35,  1907. 

('07)  Berger,  E.  W.  Whitefly  Conditions  in  1906.  Fla.  Agr.  Exp.  Sta.  Bui.  88, 
1907. 

('07  >  Berger,  E.  W.  Control  of  Whitefly  by  Natural  Means.  Fla.  State  Hort. 
Soc.  Rept.,  pp.  73-78,  1907. 

('07)  Fawcett,  H.  S.     Fla.  Agr.  Exp.  Sta.  Rept,  p.  xlvii,  1907. 

('08)  Rolfs,  P.  H.  and  Fawcett,  H.  S.     Fla.  Agr.  Exp.  Sta.  Bui.  94,  1908. 

VERTICILUUM    HETEROCLADUM    PENZ. 

('82)    Penzig,  O.     Flora  Italica,  t.  1193,  Mich.  II,  p.  462,  1882.* 

('86)    Saccardo.     Sylloge  Fungorum,  IV,  p.  151,  1886. 

('87)  Penzig,  O.  Studi  Botanici  sngli  Agrumi  e  sulle  Plante  Affini,  p.  398, 
Tavola  xli,  Fig.  3,  Roma,  1887. 

('04)  Gueguen,  L,es  Champignons  parasites  de  1'homme  et  des  animaux,  p.  252, 
Paris,  1904.* 

('06)    Parkin,  J.     Ann.  Roy.  Bot.  Gard.  Peradeniya,  Vol.  Ill,  Part  I,  p.  45,  1906. 

('07)  Fawcett,  H.  S.  The  Cinnamon  Fungus  of  the  Whitefly.  Fla.  Agr.  Exp. 
Sta.  Press  Bulletin  76,  1907. 


SPHAEROSTILBE   COCCOPHILA 

('48)  Desmazieres.     Ann.  des  Sc.  Nat.,  Tome  x,  p.  359,  1848. 

('65)  Tulasne.     Carpologia,  Vol.  Ill,  p.  105,  1865.* 

('S3)  Saccardo.     Sylloge  Fungorum,  II,  p.  513,  1883. 

('92)  Cooke,  M.  C.  Vegetable  Wasps  and  Plant  Worms,  p.  322,  Plate  2,  Fig.  22, 
London,  1892. 

('92)      Cockerell,  T.  D.  A.     Bui.  Bot.  Dept.  Jamaica,  No.  36,  p.  6,  1892. 

('92)  Ellis  and  Everhart.     North  American  Pyrenomycetes,  p.  Ill,  1892. 

('94)  Tryon,   H.     Queensland  Dept.  of  Agr.,  Bui.  4,  p.  15,  1894. 

('96)  Rolfs,  P.  H.     Fla.  Agr.  Exp.  Sta.  Rept.,  p.  49,  1896. 

('97)  Rolfs,  P.  H.  A  Disease  of  the  San  Jose  Scale.  Fla.  Agr.  Exp.  Sta.  Bui.  41, 
1897. 

('97)      Craig,  J.     Canadian  Exp.  Farm  Rept.  119,  1897. 

('97)  Smith,  J.  B.     New  Jersey  Agr.  Exp.  Sta.  Rept.  18,  pp.  470-479,  1897. 

('98)  Smith,  J.  B.     New  Jersey  Exp.  Sta.  Rept.  19,  pp.  445-446,  1898. 

('98)  Rolfs,  P.  H.     Fla.  Agr.  Exp.  Sta.  Rept.,  p.  7,  1898. 

('98)  Forbes,  S.  A.     111.  Agr.  Exp.  Sta.  Bui.  56,  pp.  270-280,  1898. 

('98  )  Webster,  F.  M.     Ohio  Agr.  Exp.  Sta.   Bui.  103,  p.  198,.  1898. 

('99)  McAlpine,  D.  Fungus  Diseases  of  Citrus  Trees  in  Australia.  Dept.  of  Agr. 
Queensland,  p.  113.  Figs.  181-182,  pp.  27  and  28,  1899. 

('00)     Rolfs,  P.  H.     Proc.  Fla.  State  Hort.  Soc.,  p.  65,  1900. 

('00)  Earle,  F.  S.     Ala.  Agr.  Exp.  Sta.  Bui.  106,  p.  175,  1900. 

('00)  Gossard,  H.  A.     Fla.  Agr.  Exp.  Sta.  Rept.  1899-1900,  p.  55,  1900. 

('00)  Gossard,  H.  A.     Fla.  Agr.  Exp.  Sta.  Bui.  51,  p.  125,  1900. 

('01)  Fuller.     First  Rept.  of  Gov.  Entomologist.    Dept.  of  Agr.,  Natal,  p.  99,  1901. 

('01)  Gossard,  H.  A.     Fla.  Agr.  Exp.  Sta.  Rept,  p.  63,  1901. 

('02)  Gossard,  H.  A.     Fla.  Agr.  Exp.  Sta.  Bui.  61,  pp.  479,  487-491,  1902. 

('03)  Gossard,  H.  A.     Fla.  Agr.  Exp.  Sta.  Bui.  67,  p.  623,  1903. 

('03)  Earle,  F.  S.     Ann.  Rept.  Off.  of  Exp.  Sta.,  p.  457,  Washington,  D.  C.,  1903. 

('03)  Smith,  J.  B.     New  Jersey  Exp.  Sta.  Rept.  24,  p.  567,  1903. 

('04)      Rolfs,  P.  H.     Proc.  Fla.  State  Hort.  Soc.,  p.  63,  1904. 

('04)  Hume,  H.  H.  Citrus  Fruits  and  Their  Culture,  p.  548,  Jacksonville,  Flor- 
ida, 1904. 


40  FUXf.I    PARASITIC  UPON  ALEYRODES  CITRI. 

MM)    Kuwaiia.  S.  I.    Japan  Imp.  Agr.  Exp.  Sta.  Kept,  p.  26,  1904. 

('05)    Sellards,  E.  H.     Fla.  Agr.  Exp.  Sta.  Kept,  p  27,  1905. 

('06)     Earle,   F.   S.     Primer  Informe  Anual  de  la  Estacion  Central   Agronomic* 
de  Cuba,  l'.n>4-l  «.»(»:•.  p.  ]<•>:>.  i<>06. 

(  •(>«•, )    Parkin,  J.   Ann.  Roy.  Bot.  Card.  Peradeniya.    Vol.  Ill,  Part  I,  p.  48-49,  1906. 

(•()7)    Berger,  E.  W.     Fla.  Agr.  Exp.  Sta.  Rept.,  pp.  31,  36,  37,  1907. 

( '(i7  )      Berger,  E.  \V.     Proc.  Fla.  State  Hort.  Soc.,  p.  71,  1907. 

(•(»7)    Berger,  E.  W.     Whiterly  Conditions  in  1906.     Fla.  Agr.  Exp.  Sta.  Bui.  88, 
1>.   :>4.    1907. 

:)    Griffing.    Fla.  State  Hort.  Soc.  Rept,  pp.  54-55,  1907. 

('08)    Cook,  M.  T.  and  Home,  W.  T.     Insects  and  Orange  Diseases.     Cuba  Exp. 
Sta.   Bui.  9,  p.  22,  February,  1908. 

('DM    Howard.  C.  W. "  The  Scale  Insects  of  Citrus  Trees.     Dept.  of  Agr.,  Trans- 
vaal.    Reprint  from  Transvaal  Agr.  Jour.  No.  148,  p.  6,  1908. 

MIX)     Rolfs,   P.   H.  and  Fawcett,   H.   S.     Fungus   Diseases  of   Scale   Insects  and 
Winterly.     Fla.  Agr.  Exp.  Sta.  Bui.  94.   I'.ios. 

MICROCERA    SP. 

('07)    Fawcett,  H.  S.     A  New  Whiterly  Fungus.     Fla.  Agr.  Exp.  Sta.  Press  Bui. 
No.  68,  1907. 

WKI'.r.Kk's    I'.KOWX    FUNGUS. 

"i)  Webber,  H.  J.     Proc.  Fla.  State  Hort.  Soc.,  p.  74,  1896. 

( '97 )  Webber,  H.  J.     Proc.  Fla.  State  Hort.  Soc.,  pp.  55-56,  1897. 

(<(.»7)  Webber,  H.  J.     Sooty  Mold  of  the  Orange.     Div.  of  Veg.  Phys.  and  Path., 
Washington.    I).  C.,   Bui.   13,  pp.  27-30,  1897. 

('00)  Pettigrew,  A.  J.     Proc.  Fla.  State  Hort.  Soc.,  p.  63,  1900. 

('<><»'  Hume,  H.  H.     Fla.  Agr.  Exp.  Sta.  Bui.  53,  p.  164,  1900. 

('03)  Gossard,  H.  A.     Fla.  Agr.  Exp.   Sta.  Bui.  67.  pp.  621-622,  1903. 

( '()4  )  Hume.  H.  H.     Citrus  Fruits  and  Their  Culture,  p.  550,  Jacksonville,  Flor- 
ida, I'.HM 

)  Sellards.  E.  H.     Fla.  Agr.  Exp.  Sta.  Rept.,  p.  26,  1905. 

( '(Mi )  Parkin,  J.     Fungi  Parasitic  Upon  Scale  Insects.     Annals  of  Roy.  Bot.  Card.. 
Peradeniya.  Vol.  III.  Part  I.  p.  52,   190(5. 

('or.)  Merger,  E.  W.     Fla.  Agr.  Exp.  Sta.  Rept.,  p.  xix.  1906. 

(  'i»7  )  Berger,  E.  W.     Fla.  Agr.  Exp.  Sta.  Bui.  88,  pp.  64-65,  1907. 

('07)  Berger,  E.  W.    Fla.  Agr.  Exp.  Sta.  Rept.,  p.  xxxi,  1907. 

('08)  Rolfs.   P.   H.  and   Fawcett,   H.   S.     Fungus  Diseases  of  Scale  Insects  and 

Whitefly.  Fla.    A-r.    Kxp.    Sta.    liul.   <)4.    1908. 

i-Xl'l.  \.\.\TIO.\  oi?  PLATES. 
PLATE  I. 

Fig.  20. — .  Isclicrsnnid  tilcyi'<)dis.  Culture  in  petri  dish  of  5  per  cent,  glucose  agar 
pourc-d  December  7.  1900;  showing  mature  stroma  36  ..days  old.  The  central 
raised  portion  was  red,  and  contained  the  pycnidial  cavities  with  spores. 

Fig.  21. — Aschcrsonia  aleyrodis.  Culture  on  rice  after  5  weeks,  grown  at  room- 
temperature. 

Fig.  22. — Asclicrsotiiu  aleyrodis.  Culture  on  sweet  potato  plug,  after  5  weeks- 
Grown  in  refrigerator  after  first  few  days 

Fig.  23.— .  Isclicrsonia  ali-ynniis.  Culture  on  white  corn  meal  after  5  weeks.  Grown, 
at  room  temperature. 

PLATE  II. 

Fig.  24.— .  Ischt'i-stnini  fltirn-citrina.     Citrus   leaf  showing  stromata  of  the   fungus 
in   the   position    originally   assumed   by   larvae   of  .-llcynnics   citri.      The  hemi- 
spherical  raided  center  was  yellow   with  a   fringe  of  outgrowing  hyphae. 
.':> .--.Jsclicrsitnia  dlcynxlis.     Citrus  leaf  showing  stromata.     The  raised  center 
was  red  instead  of  yellow,  as  in  the  previous  figure. 

111. 

•M.—.tsc/u'rs<niia   t'laro-cifrimi.     Culture  on   petri   dish  of  5   per  cent    glucose 
agar  made  -fO.5  to  plienolphthnlein.  after  :;:;  days.     Culture  poured  September 
14.    ]'.»<><;;   showing   the   mature   stromata  one  and  a  half  times  natural   size. 
Fig.   ZT.—Aschtrsonia   flavo-citrnta.     Culture  on   petri   dish   of  5  to   10   per   cent 
glucose   agar,    after    in   days    showing   how    stromata    will    spread    when   given: 
room  to   grow. 


EXPLANATION    OF   PLATES.  41 

PLATE  IV. 

Figs.  28-30. — Aschersonia  flavo-citrina.     Cultures  on  sweet  potato  plugs,  inoculated 

November  1,   1906,  after  60  days. 
Fig.    31. — Verticillium    heterocladum.      Citrus    leaf    showing    fungus    pustules    on 

larvae  of  Aleyrodes  citri. 

PLATE  V. 

Fig  32. — rcrticillium  heterocladum.     Culture  in  test-tube  on  bread. 

Fig.  33.— Verticillium  heterocladum.     Culture  in  test-tube  on  Irish  potato  plug. 

Fig.    34. — Verticillium    heterocladum.      Culture    on   glucose    agar,    showing   brown 

pustules. 

Fig.  35. — Verticillium  heterocladum.     Leaf  of  privet  bearing  larvae  of  Aleyrodes 
citri  infected  with  the  fungus  by  means  of  a  citrus  leaf  containing  pustules. 

PLATE  VI. 

Fig.    36. — Sphaerostilbe    coccophila.      Sporodochia    of    the    fungus    on    bodies    of 

Aspidiotus  hederae,  on  Chinaberry  twig. 
Fig.  37. — Sphaerostilbe  coccophila.     Sporodochia  of  fungus  on  bodies  of  Mytilaspis 

citri co la  on  citrus  twig. 
Fig.   38. — Sphaerostilbe   coccophila.      Perithecia   of   fungus   on  Mytilaspis   citricola 

on  bark  of  citrus.     Twice  natural  size. 
Fig.  39  and  40. — Microcera  sp.     Cultures  on  rice  showing  loose  fluffy  growth  on 

top  of  medium.     Natural  size. 
Fig.  41. — Microcera  sp.     Citrus  leaf  with  larvae  of  Aleyrodes  citri  infected  with 

the  fungus.     The  fungus  is  shown  by  white  fringes  on  the  edges  of  a  number 

of  the  larvae. 

PLATE  VII. 

Fig.  42. — The  Brown  Fungus  of  Webber.     Citrus   leaf  with  brown  pustules  that 

have  formed  on  larvae  of  Aleyrodes  citri.    (Photographed  by  H.  H.  Hume.) 
Fig.    43. — Cladosporium    sp.     A    super-parasite    found   growing   over   Aschersonia, 

flavo-citrina  on  leaf  of  citrus. 


Plate  I 


Figs.  20-23.     Cultures  of  Aschersonia  aleyrodis. 


Plate  II 


Fig.  24.     Aschersonia  flavo-citrina  on  citrus  leaf. 


Fig.  25.     Aschersonia  aleyrodis  on  citrus*  leaf. 


Plate  III 


Fig.  20.     Cultures  of  Aschersonia  flavo-cilrina. 


Plate  III— Continued 


Fig.  27.     Cultures  of  Aschersonia  flavo-citrina. 


Plate  IV 


Figs.  28-30.     Cultures  of  Aschersonia  flavo-citrina. 


35 


Figs.  32-34.     Cultures  of  Verticillium  heterocladum . 
Fig.  35.      Verticillium  heterocladum  on  Aleyrodes  citri  on  privet  leaf. 


Plate  VI 


i-l 


Figs.  36-37.     Sporodochia  of  Sphaerostilbe  coccophila. 

Fig.  38.     Perithecia  of  Sphaerostilbe  coccophila. 

Figs.  39-40.     Cultures  of  Microcera  sp. 

Fig.  41.     Microcera  sp.  on  Aleyrodes  citri  on  citrus  leaf. 


Plate  VII 


Fig.  42.     Brown  fungus  on  Aleyrodes  citri. 


1-3 


Fig.  43.     A  super-parasite  (Cladosporium  sp.)  upon  Aschersonia  flavo-citrina. 


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